Scientific and technical cooperation

SCIENTIFIC AND TECHNICAL COOPERATION

 

Open International University of Human Development 'Ukraine'

Prof., doctor of technical sciences Victor Malyshev

Director of Institute of Engineering & Technology

23 Lvivs’ka Str.

03115 Kyiv, Ukraine

Tel/ Fax: +38044 4249433

E-mail: victor_malyshev@mail.ru

 

New materials on the base of zirconium and titanium borides: obtaining, properties, application 

 

The high temperature electrochemical synthesis (HTES) of new superhard materials on the base of zirconium and titanium diborides is based on multielectron processes leading to the electro­deposition of metals and nonmetals from ionic melts. The lack of information on the theoretical basis and on the controlling principle of both multielectron processes and HTES had initially prevented the practical application of electrosynthesis methods. However, the systematic data on the multielectron processes leading to the deposition of refractory metals and nonmetals obtained during the last two decades have provided a scientific basis, which has stimulated an increasing interest in the problems of HTES.

An analysis of HTES state and problems made and published earlier (Malyshev V.V., Kushkov H.B., Shapoval V.I. High-Temperature Electrochemical Synthesis of Carbides, Silicides and Borides of VI-A group metals in ionic melts // J.Applied Electrochemistry. - 2002. - V.35, No. 5. - P. 573-579) has shown that as a rule electrosynthesis is carried out by a purely empirical choice of melt composition and of experimental conditions. The very small num­ber of publications (approximately 20) devoted to this problem is note worthy. However, in the whole of this work no reference can be found to the mechanism and to the controlling principles of HTES processes, without which the practical application of the method is severe limited.

Technologies which were elaborated allow to deposit superhard and temperature-resistant coatings of zirconium and titanium borides and to form disperse powders of these borides.

Within the project framework high-temperature electrochemical deposition of zirconium and titanium diborides in the form of powders or coatings from ionic melts depending on temperature, cathodic current density and duration of process, and also relations of these parameters with deposition rate, physico-chemical properties of deposits will be investigated. Electrochemical deposition consists in electrolysis of zirconium, boron and titanium compounds at temperature 700-800°С and cathodic current density of 0.01-1.00 А/m2.

Scope: technologies of obtaining of zirconium and titanium diborides in the form of powders or coatings from ionic melts.

Objectives: powders and coatings of zirconium and titanium diborides.

1. Fine powders of Zr and Ti diborides with the following intended characteristics:

1.1  Specific surfase area of the powders 5-20 m2g-1

1.2  Current yield 80-95%

1.3  High abrasion ability

1.4  Additional grinding and binder for pressing are not needed

2. Coatings of zirconium and titanium diborides on different construction metallic materials

2.1  Coating thickness in the case of ordinary electrolysis – up to 100-200 mkm in the case of reversing electrolysis – up to 500 mkm

 

The increased interest in new environmentally safe technologies for producing and processing of superhard materials is due to their important applied properties. Refractoriness, corrosion resistance, wear resistance, hardness of their components make them promising inorganic materials in the new developing fields of technology were high temperature, velocities, loans and aggressive environments are used.

 

The contribution to the fundamental science:

  1. Thermodynamic analysis of electrochemical reactions and calculation of isolation potentials  of different compounds of Zr, Ti, B within the 298-1200 K temperature interval and adding data into the databases of electrochemists.
  2. Thermodynamic prediction and experimental search of multi-electron systems and equlibria realization conditions.
  3. Establishment of the mechanism of formation and reduction of electrochemically active particles (ECAP).
  4. Study of the composition and structure of complex mono-, poly- and heteronuclear particles.
  5. Development of methods of moving together and superposition of potentials of partial processes of synthesis components reduction.
  6. Development of theoretical and experimental basis for HTES (identification of possible variants and regimes of the electrolysis and selection of components for the synthesis).

 

The contribution to applied science:

  1. Production of titanium and zirconium diborides both in the form of powders and in the form of coatings by electrolysis of new ecologically safe electrolytes. Recommendations for new practically important technological process will be elaborated.
  2. Creation of closed-circuit technologies. Possibility to use wastes and secondary raw materials.
  3. Possibility of use of relatively inexpensive compounds.
  4. Optimization of electrolizers design, construction materials, and electrolysis conditions (temperature, cathodic and anodic current density, electrolytes compositions, electrolysis atmosphere).
  5. Investigation of physico-chemical properties, crystal structure and performance characteristics of produced powders and coatings (wear resistance, hardness, abrasive resistance). Inclusoin of produced materials into the catalogue of industrial materials.

 

Economic benefits:

  1. significant decrease of synthesis temperature down to 973-1073 K (in comparison with temperature higher than 1273 K in the known synthesis methods);
  2. availability and cheapness of technological raw material (in contrast to methods of gaseous phase saturation)

The implementation of scientific and applied tasks is interrelated and they will be performed simultaneously. Their symbiosis pursues the common goal: to develop competitive environmentally appropriate technologies for producing a new class of superhard materials and their introduction in industry.

The importance of the project for the participating countries (taking into account the interconnection of the scientific and applied tasks of all participants) supposes the necessity of its financing within the framework of a single project.

Besides scientific and technological benefits, the project fulfilment will promote the increase of scientific potential of parties and the application of promising technologies in the industry of both the countries-partners.

 

 


 

SCIENTIFIC AND TECHNICAL COOPERATION

 

Open International University of Human Development 'Ukraine'

Prof., doctor of technical sciences Victor Malyshev

Director of Institute of Engineering & Technology

23 Lvivs’ka St.

03115 Kyiv, Ukraine

Tel/ Fax: +38044 4249433

E-mail: victor_malyshev@mail.ru

 

New coatings and fine powders based on alloys and intermetallides of molybdenum (tungsten) with cobalt (nickel): obtaining, anode dissolving, corrosion

 

Investigation of electrorteduction, electrooxidation, and corrosion of refractory metals (molybdenum, tungsten, nickel, cobalt) and synthesis of disperse powders and coatings based on these materials. Project concerns the area of the chemistry and electrochemistry of aqueous and molten electrolytes, of the refractory compounds synthesis as disperse powders and as coatings by electrochemical nanotechnologies.

High-temperature electrochemical synthesis (HTES) of superhard alloys and intermetallides "molybdenum (tungsten) – cobalt (nickel)" as disperse powders and as galvanic coatings on different metal materials is based on the following:

  1. Thermodynamic calculations of electrochemical synthesis reactions;
  2. Realization of multielectrom processes of electroreduction of molybdenum, tungsten, cobalt, and nickel;
  3. Overlapping of synthesis components partial electroreduction processes and their simultaneous realization;
  4. Investigation of synthesis components electrooxidation and corrosion processes in the aqueous electrolytes and melts.

Problem state analysis have shown that hitherto abovementioned compounds synthesis is realized only in aqueous solutions. Limitations of such processes are impossibility to control precisely the deposit phase composition and possibility to obtain the final product only as powder. Preliminary thermodynamic calculations and laboratory studies of Mo, W, Co, and Ni electrodeposition and electrodissolution have shown that mentioned disadvantages could be eliminated by development of new aqueous electrolytes and replacement of aqueous electrolytes by  molten salts.

Development of new electrochemical nanotechnologies of "molybden (tungsten) – cobalt (nickel)" alloys and intermetallides synthesis is caused by these materials properties being prospective for contemporary technique and production. Hardness, wear resistance, corrosion resistance, and thermal stability of these materials make them prospective inorganic materials. Today these compounds synthesis is realized through either aqueous solutions electrolysis or direct synthesis from components. Both methods have certain disadvantages (difficulties in process control and in regulation of products composition, possibility of final product obtaining either only as disperse powder or only as coating). HTES method allows to eliminate these disadvantages and also has some additional advantages, namely:

1)      possibility to use closed-cycle technologies and continuous processes;

2)      significant decrease of synthesis and electrodeposition temperature (down to 800-900°C;

3)      availability of synthesis reactants and possibility to use waste products.

Objects under investigation: heat-resistant, superhard, wear- and corrosion-resistant alloys and intermetallides based on molybdenum, tungsten, nickel, and cobalt.

  1. Disperse powders with the following properties:

1.1.     Powders surface area 10-25 m2/g;

1.2.    Product yield during elecrolysis 75-95%;

1.3.    High refractoriness and heat resistance;

1.4.    Abitity to be pressed without any cohesive.

      2. Different constructional materials surfaces coatings based on alloys and intermetallides of molybdenum, tungsten, nickel, and cobalt with the following characteristics:

2.1.    Mo-Ni alloys and intermetallides microhardness (kg/mm2) within the limits of 170-715 (depending on cathodic product composition), W-Ni alloys and intermetallides microhardness (kg/mm2) within the limits of 120-925, Mo-Co alloys and intermetallides microhardness (kg/mm2) within the limits of 105-620, W-Co alloys and intermetallides microhardness (kg/mm2) within the limits of 160-820;

2.2.    Constructional materials surfaces coatings thickness up to 50-100 mm.

Development of the proposed new technologies is based on the solution of the following problems:

  1. Development of the scientific background (thermodynamic analysis of synthesis components electroreduction reactions and electrochemical study) of HTES of alloys and intermetallodes "Mo (W) – Ni (Co)";
  2. Development of HTES and electrodeposition technologies of alloys and intermetallodes both as disperse powders and as coatings on the surface of different constructional materials;
  3. Development of laboratory techniques for target products obtaining:

3.1.    Selection of the bath composition

3.2.    Optimization of electrolyzers constructions and selection of construction materials depending on electrolysis conditions;

3.3.    Development of flow diagrams for the production of powders and coatings of certain composition;

3.4.    Investigations of physico-chemical properties and performance characteristics of materials produced.

Results, expected to be achieved

The contribution to fundamental science:

  1. Thermodynamic analysis of electrochemical reactions and calculation of decomposition potentials (voltages) of different compounds of Mo, W, Co, and Ni within wide temperature interval.
  2. Thermodynamic prediction and experimental search of conditions of multi-electron processes and equlibria realization with participation of Mo, W, Co, and Ni by methods of potentiometry and voltammetry.
  3. Determination of the mechanism of formation and discharge of electrochemical active particles (ECAP) by electrochemical methods.
  4. Study of the composition and structure of aqueous solutions and ionic melts in which the synthesis and electrodeposition of components is carried out.
  5. The development of methods of approximating and joining the potentials of partial processes for reduction of the synthesis components.
  6. Investigation of electrooxidation and corrosion mechanisms for Mo, W, Co, and Ni in aqueous solutions and ionic melts.
  7. The development of theoretical basis for electrochemical synthesis of alloys and intermetallides of Mo or W with Ni or Co.

 

The contribution to applied science:

  1. Production of Mo, W, Ni, and Co powders and coatings, and also of their alloys and intermetallides at surface of different metallic constructional materials.
  2. Creation of closed-circuit technologies. Possibility to use secondary raw materials.
  3. Selection of corrosion-resistant metals and compounds for constructional materials for electrolyzers and of materials of soluble anodes for electrolysis carrying out.
  4. Optimization of electrolyzers constructions and electrolysis conditions (temperature, cathodic and anodic current density, bath compositions, atmosphere over the bath) in aqueous solutions and molten salts.
  5. Investigations of physico-chemical properties and performance characteristics of produced powders and coatings.

Accomplishment of scientific and applied tasks is closely interrelated, and they are realized simultaneously. Their symbiosis promotes the cooperation goal achievement. Importance of the project for the both sides requires some kind of close mutually advantageous collaboration. Besides scientific and technical results, project will promote improvement of both parties scientific potentials and introduction of prospective technologies to the industry of both countries.

Expected results

1. Thermodynamic analysis of electrochemical reactions and calculation of synthesis electrochemical diagrams for HTES of alloys and intermetallides of Mo, W, Ni, and Co, and also thermodynamic backgrounding of possibility of these metals electrodeposition onto different substrates.

2. The mechanisms of formation and discharge of electrochemically active particles and their classification.

3. Methods of approximating and joining of the potentials of partial processes of synthesis components deposition.


4. Mechanisms of anodic dissolution and corrosion of Mo, W, Ni, and Co inionic melts.


5. Electrodeposition of Mo, W, Ni, and Co in the form of disperse powders and of coatings on the surface of constructional materials.


6. Physico-chemical properties and performance characteristics of produced powders and coatings.

 

The results obtained will be presented in international chemical and materials science journals and will be discussed at international conferences on molten salts and ecological monitoring. Lectures and practical lessons will be planned for students and employees of both the institutions participating in the project. Project accomplishment is planned with wide participation of students whose diplomas are closely related to project subjects. Patenting, technologies transfer to other countries, and protection of intellectual property rights will be realized.

Advantages of cooperation

Professional education of scientist The possibility of cooperation with foreign research team which specializes in similar scientific sphere and whose scientific methodological approach differs from our approach, will give undoubtedly positive results in solving quite a number of scientific and practical problems. This possibility is to be considered desirable and useful.

We expect that after completion of the project the positive original results obtained will form the basis for 1 thesis for a doctor’s degree, for 2 thesis for a candidate degree, and for 3 master degree diploma compositions of joint-project participants.

Prospects of International level Cooperation in project realization will promote both parties (and probably other partners) in the diferent European and international programs (INTAS, CRDF, Copernicus, STCU).

 


 

SCIENTIFIC AND TECHNICAL COOPERATION PROJECT

Open International University of Human Development «Ukraine»

Prof., doctor of technical sciences Victor Malyshev

Director of Institute of Engineering & Technology

23 Lvivs’ka St.

03115 Kyiv, Ukraine

Tel/ Fax: +38044 4249433

E-mail: victor_malyshev@mail.ru

 

New non-polluting and resource-saving technologies of synthesis and processing in ioinc melts of superhard materials for the tool making and chemical industries  

 

The high temperature electrochemical synthesis (HTES) of superhard materials is based on multielectron processes leading to the electrodeposition of metals and nonmetals from ionic melts. The lack of information on the theoretical basis and on the controlling principle of both multielectron processes and HTES had initially prevented the practical application of electrosynthesis methods. However, the systematic data on the multielectron processes leading to the deposition of high melting metals and nonmetals obtained during the last two decades have provided a scientific basis, which has stimulated an increasing interest in the problems of HTES.

An analysis of the state of problems in HTES has shown that as a rule electrosynthesis is carried out by a purely empirical choice of melt composition and of experimental conditions. The very small number of publications (approximately thirty) devoted to this problem is note worthy. However, in the whole of this work no reference can be found to the mechanism and to the controlling principles of HTES processes, without which the practical application of the method is severe limited.

Study objectives: group VI-B metals carbides and borides, hard alloys WC-Co

1.   Fine powders of Mo, W carbides and dorides with the following intended characteristics:

1.1     Specific surfase area of the powders 5-20 m2g-1

1.2     Current yield 80-95%

1.3     High polishing ability

1.4     Additional grinding and binder for pressing are not needed

1.5     May be used as possible substitute for platinum catalysts in the reactions of organic and inorganic synthesis.

2.   Coatings of Mo, W carbides on different construction materials and on fine powders of Si and B carbides with the following intended characteristics:

2.1     Microhardness (kg.mm-1) Mo2C – 1800-2100; W2C –  2900-3100

2.2     Coating thickness on construction materials in the case of ordinary electrolysis – up to 100-200 mm in the case of reversing electrolysis – up to 500 mm

2.3     Coating thickness on granulars of fine materials – up to 5 mm

3.   Superhard alloys WC-Co, their raw and recycled materials processing

The increased interest in new environmentally safe technologies for producing and processing of superhard materials is due to their important applied properties. Refractoriness, corrosion resistance, wear resistance, hardness of their components make them promising inorganic materials in the new developing fields of technology were high temperature, velocities, loans and aggressive environments are used.

Among the existing production methods, one of the last developed (but still with potential) is high-temperature electrochemical synthesis (HTES) from molten salts. The advantages of the method are:

1.   The possibility to effect an environmentally appropriate waste-free closed-circuit technology.

2.   High purity of end products with impure starting reagents.

3.   The possibility to effect a continuous process

4.   Decrease in synthesis temperature to 750-800oC

5.   The possibility to produce the material as coatings on products of any shape and as fine powders

The development of the proposed new technologies is based on the solution of the following questions:

1.   Development of the scientific background (thermodynamic analysis and voltammetric study) of HTES superhard materials

2.   Development of technologies of carbides HTES

2.1     Selection of the bath composition

2.2     Optimization of construction materials an electrolysis conditions

2.3     Development of flow diagrams for the production of powders and coatings of materials

2.4     Investigations of physico-chemical properties and performance characteristics of materials produced

2.5     Regeneration of waste materials by anode dissolving in ionic melts.

 

Environment friendly synthesis of ultrahard materials for machining and polishing

 

Superhard materials like tungsten carbide, titanium carbide, diamond, cubic boron nitride, etc. are used for machining and polishing of metallic parts world-wide. However, the superhard materials used today by the tool industry are still expensive (the cheapest tungsten carbide sintered with cobalt costs over 100 ECU per kg). Also, ecological issues concerning technologies of production and переработки of such superhard materials become more and more serious. On the other hand, a new synthesis technique is being developed at laboratory scale by some laboratories. The technique involves electrochemical synthesis of carbide of boride phases from molten salts in which are produced either as adherent coatings or powders.

The target of the present project is to couple the know-how and market experience of the major industrial partners in this field with the academic knowledge of scientists. The objective is therefore the development of new, cheap and environment friendly production of superhard materials (coatings and sintered tools) for machining and polishing applications.

From this molten salt electrochemical synthesis, a large range of carbide and boride phases can be produced at very low cost and at low total energy consumption level. The reason for that is that the salts used as starting materials in this technology are far cheaper than the expensive pure elements as in other conventional techniques (CVD, PVD, powder metallurgy): for instance this new method makes it possible to produce tungsten carbide in one step instead of two.

The low overall energy consumption of this electrochemical processes also results in a lesser environmental damage compared to classical methods.

In the proposed project the cooperation of industrial and scientific partners with their counterparts will result in the following expected benefits:

1.   to work out an electrochemical synthesis + sintering technique of production of tungsten carbide parts, providing a cheaper produced with less environmental damage, with avoiding the usage of bonding materials upon sintering like cobalt and nickel, which are detrimental to environment;

2.   to work out an electrochemical synthesis + sintering technique of production of other carbide (pure and mixed) parts, providing a cheaper product with improved service characteristics and produced with less environmental damage;

3.   to work out a technique of electrochemical anode dissolving of production wastes and recycled superhard materials with components re-using in industry.

Expected contribution to fundamental science:

1.   Thermodynamic analysis of electrochemical reactions and calculation of decomposition potential (voltage) of different compounds of every individual component (Mo, W, B, C) at the 900-1200 K temperature interval will serve as thermodynamic grounds of search of multielectron systems with one and more components for HTES.

2.   Experimental search of multi-electron systems and equlibria will be realized by methods of potentiometry and voltammetry.

3.   The mechanism of formation and discharge of electrochemical active particles (ECAP) will be studied by electrochemical methods. As a result the different formation mechanism of complex mono- and poly-nuclear ECAP will be classified.

4.   Electrochemical methods will allow to suppose the composition and structure of complex mono- and poly-nuclear particles.

5.   The development of methods of approximating and identifying of the conditions for joining the potentials of different processes for deposition of the components.

6.   Mathematical model calculation of co-discharge of metal and non-metal ions with the following heterogeneous chemical reactions of discharge products will be formed.

7.   The development of theoretical and experimental basis for HTES (identification of possible variants and regimes of the electrolysis and selection of components for the synthesis).

8.   Experimental search of conditions of hard alloys selection dividing.

 

Expected contribution to applied science:

1.   Production of Mo, W metals, their carbides and borides in the form of powders or coatings by electrolysis from new ecologically safe electrolytes. Recommendations for new practically important technological process will be elaborated.

2.   Creation of closed-circuit technologies. Possibility to use secondary raw materials.

3.   Use of relatively inexpensive compounds, including natural oxide compounds.

4.   Optimization of construction materials and electrolysis conditions (temperature, cathodic and anodic current density, bath compositions, atmosphere under the bath).

5.   The possibility of selective переработки of hard alloys with re-using in industry.

6.   Investigations of physico-chemical properties, crystal structure and performance characteristics of produced powders and coatings (corrosion resistance, wear resistance, hardness, abrasive resistance. Creation of a catalogue of produced materials.

 

The implementation of scientific and applied tasks is interrelated and they will be performed simultaneously. Their symbiosis pursues the common goal: to develop competitive environmentally appropriate technologies for producing a new class of superhard materials and their introduction in industry.

The importance of the project for the participating countries (taking into account the interconnection of the scientific and applied tasks of all participants) supposes the necessity of its financing within the framework of a single project.

Besides scientific and technological benefits, the project fulfilment will promote the increase of scientific potential of parties and the application of promising technologies in the industry of both the countries-partners.

 


 

SCIENTIFIC AND TECHNICAL COOPERATION PROJECT

Open International University of Human Development «Ukraine»

Prof., doctor of technical sciences Victor Malyshev

Director of Institute of Engineering & Technology

23 Lvivs’ka St.

03115 Kyiv, Ukraine

Tel/ Fax: +38044 4249433

E-mail: victor_malyshev@mail.ru

 

Nanocrystalline silicides of VI group metals: new synthesis methods, physico-mechanical and chemical properties  

 

Problem statement. Silicides of refractory metals, including chromium, molybdenum, and tungsten silicides, are characterized by complex of valuable physico-chemical properties, particularly by high melting point, by significant strength parameters, by resistance to oxidation and to thermal deformation at high temperatures. These silicides are also distinguished by many technically important properties, namely electrophysical parameters, fire, corrosion, and wearing resistance. They are promising materials for new areas of technology related to the use of high temperatures, speeds, loads, corrosive environments etc. Besides, they can be possibly used as semiconductor materials with narrow (about 0.35 eV) energy gap. Due to unique abovementioned properties both of sintered bulk samples and of thin films, VIB group metal silicides are semiconductor materials being the most intensively investigated and introduced. Their use is promising in optoelectronic devices, in photovoltaic cells, and in thermoelectroconverting elements operating at high temperatures.

To date, studies of synthesis routes and of physical, mechanical, and chemical properties of chromium, molybdenum, and tungsten silicides were mainly associated with sintered samples and polycrystalline films. Traditionally, these silicides are obtained by methods of hot pressing and of arc melting. Application of these methods requires high temperatures (much above 1000ºC). But their main drawbacks are inability to obtain products with given stoichiometric composition and difficulty of obtaining of nanosized products.

Works on synthesis of nanocrystalline powders and on study of their heat-resistant characteristics are virtually absent in literature. For obtaining of nanocrystalline powders of VI B group metals silicides, plasma method of direct evaporation of refractory metals in monosilane atmosphere is used. This process requires very high temperatures (about 1500ºC) since the reaction occurs in molten medium.

Among the alternative methods of obtaining of nanocrystalline powders of VI B group metals silicides, high-temperature electrochemical synthesis (HTES) in ionic melts and metallothermic reduction of compounds of chromium, molybdenum, tungsten, and silicon by alkali and alkaline earth metals are least developed, but at the same time promising. Previous studies have shown that alkali and alkaline earth metals halides being by-products of synthesis allow to realize the synthesis in low-temperature molten medium, and, thus, nanosizes can be achieved. The average size of powders with is 60-90 and 35-60 nm for these methods, respectively. Single-crystalline nanorods 40-80 nm in diameter and about 600 nm long were also synthesized.

Among existing methods of obtaining of VIB group metals silicides, HTES and metallothermic reduction methods are the least studied, but mostly promising ones. The most significant advantages of them are as follows:

1) possibility to implement environmentally sound and resource-saving closed-cycle technologies in ionic melts;

2) high purity degree of products obtained from relatively contaminated reagents;

3) possibility to implement continuous process of synthesis and electrodeposition (for HTES method and for electrolysis of melts);

4) possibility to obtain silicides of given stoichiometric composition (depending on the ratio of the synthesis components and on the conditions of electrolysis for HTES method, and on the ratio of reducible materials and on conditions of the process for method of metallothermic reduction);

5) possibility to obtain different nanostructures (powders, rods, coatings) depending on electrolysis conditions for HTES method and on the nature of metal-reducent for metallothermic reduction method;

6) significant decrease of  temperature of synthesis and of electrodeposition (down to 650-800ºC).

HTES of transition metal silicides and electrodeposition of silicon, molybdenum, and tungsten coatings are based on data of thermodynamic calculations of electrochemical synthesis diagrams and on results of implementation of multi-electron processes of electroreduction and electrodissolution of metals and nonmetals in ionic melts. Analysis of problems of electrodeposition and of HTES have shown that, until now, they were based mainly on empirical selection of electrolyte and of conditions of electrolysis process. Small number of publications (about 20) were devoted to this subject. In literature, there is little available information on controlling of multi-electron processes and on conditions of their simultaneous implementation. This situation has greatly hindered practical application of electrochemical technologies in ionic melts. Accumulated during last 10-15 years results of thermodynamic calculations of electrochemical synthesis diagrams, of study and implementation of multi-electron processes of electrodeposition and electrodissolution of refractory metals and nonmetals become a scientific basis and impetus for the accelerated development of HTES and electrodeposition of coatings from ionic melts.

Project aim: Development of the fundamentals of new (HTES and metallothermic reduction) methods for obtaining nanocrystalline silicides of chromium, molybdenum, and tungsten and study of their physico-mechanical and chemical properties.

Objects of research: Nanostructured powders of VI-B group metals silicides and coatings based on silicon and its compounds:

1) disperse powders of silicides of chromium, molybdenum, and tungsten, which are characterized by the following properties:

1.1) powders surface area - 5-20 m2g-1;

1.2) product yield - 80-95% for electrolysis and up to 99% for metallothermic reduction;

1.3) high refractoriness and heat resistance;

1.4) nanocrystalline structure;

1.5) ability to be pressed without any binder;

2) coatings of silicon, molybdenum, and tungsten, at the surface of various structural materials with the following characteristics:

2.1) microhardness (kg•mm-2) – 160 for Si, 180 for Mo; and 310 for Mo;

2.2) thickness of coating on structural materials up to 100-200 µm in case of conventional electrolysis and up to 500 microns in the case of reversive mode.

The originality of the project is possibility to use particular synthesis method (HTES or metallothermic reduction) depending on the ultimate goal of obtaining product with preset stoichiometric composition, structure, required quantity etc.

Problem of obtaining of nanocrystalline VI-B group metals silicides can be solved in the following ways:

1) by development of specific obtaining method;

2) with obligatory taking into account principles of energy and resource conservation and of "green chemistry".

The scientific value of the project:

1. Thermodynamic analysis of electrochemical reactions and calculation of potentials (voltages) of decomposition of various compounds of chromium, molybdenum, tungsten, and silicon in a wide temperature range (298-1200K).

2. Thermodynamic prediction and experimental search of conditions of multi-electron processes and equilibria in ionic melts.

3. Thermodynamic analysis of reactions of reduction of compounds of silicon and group VI-B metals by metals-reducents of different nature (alkaline and alkaline-earth metals, aluminum etc.).

4. Establishment of mechanisms for the formation and subsequent reduction of electrochemically-active particles (EAP).

5. Study of composition and structure of mono-, poly- and heteronuclear complexes in ionic melts.

6. Development of methods of approximation and combination of partial processes of synthesis components reduction.

7. Establishment of mechanism of metallothermic reduction and of subsequent synthesis.

8. Development of theoretical foundations of HTES and of metallothermic reduction (possible options and modes of electrolysis and reduction, forecasting synthesis components and possible products etc.).

The practical value of the project:

1. Obtaining of coatings of silicon, molybdenum, and tungsten on various structural metal materials, synthesis of powdered refractory silicides of transition metals using new environmentally friendly and resource-saving electrolytes; practical recommendations for realization of the most important processes.

2. Development of closed-cycle technologies; possibility to use wastes and recycled materials.

3. Possibility to use relatively cheap compounds (including naturally occurring oxide ones).

4. Optimization of electrolyzers design, of structural materials, and of electrolysis conditions (temperature, cathodic and anodic current density, electrolyte composition, atmosphere above bath etc.), and also of reduction (nature of metal-reducent, temperature, duration etc.).

5. Study of physic-chemical (especially corrosion resistance) and performance characteristics of synthesized powders and coatings, introducing them into industrial materials specification.

 


 

SCIENTIFIC AND TECHNICAL COOPERATION PROJECT

Open International University of Human Development «Ukraine»

Prof., doctor of technical sciences Victor Malyshev

Director of Institute of Engineering & Technology

23 Lvivs’ka St.

03115 Kyiv, Ukraine

Tel/ Fax: +38044 4249433

E-mail: victor_malyshev@mail.ru

 

Fundamental backgrounds of development of new energy-, resource-saving and environmentally friendly methods of tungsten carbide obtaining and regeneration  

 

Problem statement

Technologies of obtaining and regeneration of refractory metals carbides, as low-tonnage chemical products, can have and do have many industrial applications. World’s best practice of these materials use confirms priority of tungsten carbide among these materials.

Tungsten carbide of is one of major superhard, wearing and corrosion resistant, and catalytically active connections. For today, tungsten carbide obtaining accounts for more than 60 % of world volume of tungsten processing. In industry, tungsten carbide is obtained by two methods: metal carbidization and aluminothermic reduction of ores and concentrates. Both methods consist of a lot (more than seven) of difficult and labor intensive stages. Technology of tungsten carbide powders obtaining to be developed by method of high temperature electrochemical synthesis from melts will be free from these defects and will allow to conduct technological process continuously.

Considerable progress at hard alloys (HA) obtaining on the basis of tungsten carbide is attained by companies and scientists in Ukraine. During 1970-1990, commodity products of hard-alloy industry increased 40 times, and during 1991-2010 - 2,7 times. Before, initial components (approx. 80%) for this type of products were imported from other countries and republics of the former USSR, although in the bowels of Ukraine, there are considerable resources of necessary raw material, and also certain volumes of secondary raw materials and scrap are available in Ukraine, which usage is not enough. Therefore, it is possible to expand HA productive base due to their processing according to new technologies to be developed. Similar situation is characteristic for hard-alloy industry of EC countries.

HA of tungsten carbide with cobalt (VK) occupy one of the first places among industrial cermet HA. To recycle VK expensive components into production process, it is necessary to find possibility of secondary processing of wastes containing these components. As such wastes, matrices of exhaust boring and cutting instrument and scrap can be used. Recently, due to lack of tungsten and cobalt in Ukraine, questions of development of new methods of HA lump wastes processing become very actual. Existing methods of VK components isolation are differing not only by treatment mode but also by used chemical reagents nature. Substantial lack of group of methods of dissolution of VK components in different acids and their mixtures is toxicity of the reagents used. This shortcoming is partially removed by method of processing exhausted diamond and VK tools by anodic dissolution in hydroxide-chloride melt. Technology of isolation of cobalt and tungsten carbide by anodic dissolution in solutions of phosphoric acid to be developed, unlike molten environments, allows selective isolation of VK components and obtaining of tungsten carbide suitable for recycling into production process. Intensive predisposition of tungsten and its carbide to passivation in water solutions determines the specificity of electrochemical behavior of these compounds. Mainly, electrode potentials, cathode processes during electro-gassing, and oxidation processes with their participation were studied in solutions of hydrochloric and sulphuric acids.

Recently, obtaining of intermetallic compounds of tungsten with cobalt and nickel with broad range of physical and mechanical properties is of high priority. Today, they are produced by method of direct synthesis. Method of their obtaining by molten salts electrolysis will allow to obtain the necessary product in the form of not only powders, but also as coatings at various construction materials surface.

The aim of this project is to develop the fundamentals of new methods of production and regeneration of "low-tonnage" tungsten carbide based on different physical methods of activation of chemical processes (electrolysis, extraction, treatment by molten electrolytes, reductive gases etc.) and on principles of "green chemistry".

Project includes the development of interrelated and complementary methods for obtaining and regeneration of tungsten carbide, namely:

1)      method of separation of cobalt and tungsten carbide by anode dissolution of HA wastes in solutions of phosphoric acid for their selective isolation and obtaining of tungsten carbide suitable for recycling into production process;

2)      method of high-temperature selective extraction of tungsten from the production wastes, ores, and concentrates by dissolving in non-corrosive molten salts for selective separation of tungsten and other components between extracting phases;

3)      method of obtaining of tungsten by extracting phase electrolysis to isolate tungsten both in form of superhard dispersed catalytically active powders and as refractory, solid, wear, abrasion and corrosion resistant galvanic coatings;

4)      method of tungsten carbide obtaining through extracting phase processing by carbon containing gases to obtain dispersed powder of tungsten carbide which need no further physical-mechanical and chemical processing and is a commercial product.

This project originality consists in the ability to use different methods for tungsten carbide obtaining and regeneration, depending on the type of raw material (chemical reagents, ores, concentrates, industrial wastes) and of final product (tungsten, tungsten carbide, tungsten intermetallides with iron triad metals).

The problem of tungsten obtaining and regeneration can be solved by the following two ways:

1) development of specific method of obtaining or recovery for each source of tungsten;

2) compulsory taking into account aspects of energy and resource conservation and the principles of "green chemistry".

Description of methods. The elaboration of new methods is based on the following ideas, hypotheses and results of previous studies.

Method of separation of cobalt and tungsten carbide. Anodic dissolution method will be based on significant difference of potentials of HA components electrooxidation. Realization of electrodissolution in the potentiostatic mode will allow to leave tungsten carbide in the anodic deposit and to transfer cobalt into solution. Both intermediates are convenient to recycle HA components to into the production process.

Method of high-selective extraction of tungsten. High-temperature selective extraction (HTSE) method will be based on the distribution of components of ores and concentrates between two phases: halide-tungstate and silicate. The first phase is able to extract compounds of tungsten and the second one - oxides of iron, manganese and calcium. High manufacturability of the HTSE method is caused by two factors: by tungstates ability to mix with sodium chloride in any proportion and by extracting phases immiscibility. Phases immiscibility will allow to easily separate them from each other and to direct them to different branches of the technological scheme.

Method for tungsten obtaining. Among the metals extracted by chloride phase as a result of HTSE, tungsten has the most positive electrodeposition potential. Therefore, chloride-tungstate melt is convenient for tungsten electrodeposition both in the form of disperse powders and as coatings (depending on the conditions of electrolysis).

Method of tungsten carbide obtaining. During processing of tungsten containing melts by carbon containing gases at high temperature, one of possible pathways of tungstates interaction with compounds of carbon is formation of tungsten carbide. Obtained in previous experiments tungsten carbide was nearly stoichiometric and contains only 0.03% of free carbon. According to the data of previous sieve tests, distribution of tungsten carbide powder by fractions is as follows: 0.00-0.50 µm - 25.16%, 0.50-2.00 µm - 53.29%, 2.0-5.0 µm - 100%. Such fractions distribution is suitable for tools production by method of hot pressing without adhesive and provides high catalytic activity of dispersed powders. According to microscopic analysis data, most of the grains are twin triangular prisms. Gas-treated tungsten carbide can be easily crushed, and, thus, powder of any dispersity degree could be obtained from it, which is important for pressing and for increase of catalytic properties of the powder.

The scientific value of the project is as follows:

1. Establishing the mechanism of formation and of subsequent reduction of tungsten and carbon compounds in electrolytes of different nature (halide, halide-oxide, and oxide).

2. Study of carbide phases formation depending on the electrode material and deposition conditions (temperature, electric current parameters), and also of their interaction with materials of different conductivity nature (metals, semiconductors, and insulators).

3. Study of epitaxial growth of coatings with given crystal faces parameters and of the possibilities to control this process.

4. Establishing mechanisms of anodic dissolution of tungsten, cobalt, and alloys of tungsten carbide with cobalt depending on dissolution potential.

5. Establishing the mechanism of formation and subsequent reduction of compounds of tungsten, cobalt and nickel in electrolytes of different nature (halide, halide-oxide, oxide).

The practical value of the project is as follows:

1. Obtaining of tungsten carbide based catalysts for inorganic and organic synthesis reactions which will be competitive in comparison with existing ones.

2. Possibility to increase significantly surface hardness, wear and abrasion resistance of steel structural materials.

3. Possibility to improve significantly corrosion resistance of steel structural materials in acidic solutions and molten electrolytes.

4. Obtaining of completely new tungsten carbide coated abrasive grains of semiconductors (silicon and boron carbides) and dielectrics (boron nitride, corundum, diamond).

5. Expansion of raw materials range for HA production due to wasteless technologies and to recycling of industrial wastes, scrap, and exhausted tools.

6. Possibility of obtaining of tungsten intermetallides of desired composition in the form of both powders and coatings on structural materials surface.

Due to the project realization and to its results implementation, address the following problems of competitiveness at the domestic and international levels will be solved:

1) expansion of raw materials range for production of tungsten and its carbide due to processing of industrial wastes, of alternative raw materials (complex refractory, poor, and off-balance ores and wastes of mining industry, low-power deposits ores);

2) reducing of tungsten and cobalt deficit in Ukraine and lowering of dependency of Ukrainian industry on importation of these products from other countries and former Soviet republics;

3) development of wasteless closed-cycle environmentally friendly technologies;

4) improvement of working conditions.


 

SCIENTIFIC AND TECHNICAL COOPERATION PROJECT

Open International University of Human Development «Ukraine»

Prof., doctor of technical sciences Victor Malyshev

Director of Institute of Engineering & Technology

23 Lvivs’ka St.

03115 Kyiv, Ukraine

Tel/ Fax: +38044 4249433

E-mail: victor_malyshev@mail.ru

 

Coatings and nanostructures based on silicon, its compounds and compositions: obtaining, physico-mechanical and chemical properties  

 

Aim of the project

Development of coatings and nanostructures based on silicon, its compounds and composites methods obtaining by new ecologically safe technologies.

Project description

Silicon electrodeposition, high temperature electrochemical synthesis (HTES) of high temperature durable transition metals silicides and these metals compounds and composites, electrodeposition of Si coatings are based on thermodynamic calculation of electrochemical diagrams of synthesis and multielectron processes in ionic melts. The lack of information on the theoretical basis and on the controlling principle of both multielectron processes and HTES had initially prevented the practical application of electrosynthesis methods. However, the systematic data on thermodynamic calculationof electrochemical diagrams of synthesis, the multielectron processes leading to the deposition of high melting metals and nonmetals obtained during the last two decades have provided a scientific basis, which has stimulated an increasing interest in the problems of HTES and electrodeposition from ionic melts.

An analysis of the state of problems in HTES and in electrodeposition has shown that as a rule electrosynthesis is carried out by a purely empirical choice of melt composition and of experimental conditions. The very small number of publications (approximately 25) devoted to this problem is note worthy. However, in the whole of this work no reference can be found to the mechanism and to the controlling principles of silicide HTES processes, without which the practical application of the method is severe limited.

The increased interest in new source-saving and ecologically safe technologies for producing of transition metals silicides, their composites and electrodeposition of silicium coatings is due to important applied properties of these materials. High-temperature, corrosion, wear resistance, hardness of silicium, transition metal silicides make them promising inorganic materials in the new developing fields of technology were high temperature, velocities, loans and aggressive environments are used.

Among the existing production methods, one of the last developed (but still with potential) is high-temperature electrochemical synthesis (HTES) from molten salts. The advantages of the method are:

1.       The possibility to effect an environmentally appropriate waste-free closed-circuit technology.

2. High purity of end products with impure starting reagents.

3. The possibility to effect a continuous process of electrosynthesis and electrodeposition

4.       Decrease in synthesis and electrodeposition temperature to 750-800oC

5.       The possibility to produce the material as silicium, coatings on products of any shape and as fine powders, and nanostructures.




 

SCIENTIFIC AND TECHNICAL COOPERATION PROJECT

Open International University of Human Development «Ukraine»

Prof., doctor of technical sciences Victor Malyshev

Director of Institute of Engineering & Technology

23 Lvivs’ka St.

03115 Kyiv, Ukraine

Tel/ Fax: +38044 4249433

E-mail: victor_malyshev@mail.ru

 

New carbon dielectric materials: obtaining, galvanic processing, properties  

 

Aims and field of the project:

The main aims of the project are as follows:

1.       study of chemical and electrochemical reactions occurring at the interface carbon material (natural and synthetic diamonds, carbon nanotubes and nanorods) / ionic melt;

2.       practical application of obtained results for chemical and galvanic coatings deposition of refractory metals and their compounds onto carbon materials;

3.       Development of theoretical backgrounds of electrochemical synthesis of carbon nanotubes and nanorods in molten salts.

To achieve these aims, the following tasks are to be completed:

-        thermodynamic analysis of processes of the interaction of carbon materials with ionic melts within the temperature range 900-1200 K;

-        measuring the own conductivity of these materials at the indicated temperatures;

-        examination of the diamond surface before and after treatment by molten salts;

-        studies of chemical and electrochemical behavior of carbon materials in ionic melts to determine the conditions of their electrode potential realization;

-        selection of optimal conditions for obtaining of high-quality coatings of refractory metals and their compounds at the carbon materials surface;

-        voltammetric studies of carbonate melts to clarify kinetics and mechanism of carbonate ions electroreduction;

-        selection of optimal conditions for obtaining carbon nanotubes and nanorods by electrolysis of carbonate melts.

The project relates to the priority area of science and technology development “new substances and materials”, especially to the field of cemistry, electrochemistry, and materails science of carbon materials, and of electrochemical synthesis of carbon nanotubes and nanorods.

Object of research – chemical and electrochemical reactions at carbon electrodes, electrode potentials of carbon materials in ionic melts.

Subject of research – appearance causes, formation processes, and methods to control and use potentials of carbon electrodes as the background of obtaining and galvanic processing of carbon materials in molten salts.

The development of new technologies largely depends on the availability of modern materials. Carbon materials, including natural and synthetic diamonds, carbon nanotubes and nanorods, and also various composites based on them, have a unique set of properties: high values of thermal conductivity, hardness, radiation resistance, electrical resistance, and low toxicity. These materials are promising for use in heat engines, for manufacturing of refractory materials, of lining of baths, electrolyzers, and muffle furnaces, of abrasive tools, of high temperature semiconductors etc. Therefore, studies on the interaction of these materials with different environments and on changing their properties are of great importance and practical value because creation of quality abrasive tools with long lifetime is impossible without the use of such modified materials.

Practical application of molten salts as reaction media for deposition of coatings of refractory metals and carbides onto surface of carbon materials with different dispersion and for electrochemical synthesis of carbon nanotubes and nanorods requires a purposeful approach to the implementation and management of chemical and electrochemical processes occurring at the interface carbon material - ionic melt which makes study of these reactions especially important research task.

Investigation of the interaction of carbon materials (natural and synthetic diamonds, carbon nanotubes and nanorods) with different molten environments and consequent changes of their properties as a result of this interaction is important scientific task. It is of great practical importance since these materials are becoming more and more widely used in various industries, especially where it is necessary to deal with materials difficult to process. Creating quality abrasive tools with long lifetime is impossible without knowledge of chemical behavior of carbon materials in various environments. Most details of the such interaction processes are known for carbon materials concerning their gas phase oxidation and liquid phase treatment (by mineral acids). For ionic melts as a promising new environments, these issues are only starting to be studied.

Efficiency of abrasive tools can be considerably enhanced by improving its manufacturing technology. One of the most radical methods of improving tools efficiency is deposition of metal coating (metallization) onto carbon materials grains, including coatings of refractory metals and their compounds. Increase of durability and productivity of tools during the processing of hard alloys, tool steel, pig iron, silicon, marble, and other scarce materials difficult to process, is achieved in this case due to stronger retention of abrasive grains in the binder, to reduction of their chipping and breakoff and of thermal destruction of binder through better heat dissipation, to improving the durability of system “abrasive grain – coating”. These benefits contribute significantly better use of abrasive grains in cutting tools, especially in intensified processing modes, due to reducing specific consumption of carbon materials grains 2-6 times and increase of processing performance 1.5-2 times and more. Previous research have shown that deposition of coatings of refractory metals (molybdenum and tungsten) and their compounds onto grains of synthetic diamond materials will increase their strength 1.1-1.3 times. This capillarity materials, characterizing the relationship with the base material is increased in 1,6-1,9 times. Research party tools based on metallized synthetic diamonds have been tested in operations hruboko grinding of optical glass. Tests have shown an increase in efficiency tool 2,0-2.5 times.

Among the existing methods of deposition of metal coatings onto carbon materials (chemical and electrochemical methods for deposition of coatings from aqueous and organic solutions; methods of gas transport reactions using gaseous media based on silanes, halogenes, carbonylates; beam methods of coatings deposition from the stream of atoms or ions of the metal; mechanical cladding; coating deposition from the liquid metal melt; contact-reaction deposition using metal-catalyst etc.), electrolytic method has proved itself as one of the most promising. This is due to the possibility of deposition of coating of controllable composition and properties, to availability, reliability, and perfection of used equipment, to high performance and simplicity of electrodeposition process. However, when electrolytic method is mentioned in the literature, indirect multistage electrochemical metallization process are often implied. Major shortcoming of electgrolytic method is also weak adhesion of coating to surface of superhard materials, particularly of diamond. Coatings are deposite at low temperatures when the intensity of formation of chemical bonds between carbon and metal is negligible. Used metals have moderate or low adhesion to carbon materials. Ability to increase adhesion with heat treatment is limited. Contact strength value for such coatings with diamond surface makes only tenths of kg/mm2. Removal of these defects is possible by application of high-temperature melts. Besides, the abovementioned application will allow the use of closed cycle technologies and of continuous processes, and also of readily available reagents for synthesis and electrodeposition.

Currently, there are virtually no works devoted to the galvanic metal (or other) coatings deposition onto carbon materials from melts. Therefore, noteworthy is first information on the possibility of deposition of galvanic coatings onto dielectric ceramic materials based on zirconia, beryllium oxide, alundum, silicon oxide, and fused quartz from the system NaCl-KCl (1:1) + 4.5 mol. % MoCl3. It was shown that electrodeposition is occuring near current lead or across the whole surface of the dielectric after its previous exposure in electrolyte. Nevertheless, this method can be only conditionally called “direct electrochemical metallization” due to thin layer of conductive material - metal molybdenum – forming on the dielectric surface during exposition in the electrolyte as a result of trivalent molybdenum ions disproportionation in the melt. Actually, galvanic coating deposition is occuring at the electrically conductive substrate in this case.

Project scientific novelty will consist in the following:

1.       The selection of melts composition optimal for realizing the potential of carbon electrodes will be done on the basis of the thermodynamic analysis of the interaction of electrode material with ionic melts.

2.       Methods of management of potentials of carbon electrodes by means of changing the composition of molten electrolyte and combined electrodes structure will be developed.

3.       Experimental values of electrophysical characteristics of carbon materials obtained by method of temperature dependence of electrical conductivity, and also results of spectroscopic investigation of them before and after treatment by melts, will reveal the nature of the electrode potential of carbon electrodes.

4.       The nature of chemical and electrochemical processes occuring at the interface “carbon material – ionic melt” will be studied, and the impact of various factors on these processes will be investigated, namely:

-        correlation between the ionic bond character in dielectrics and their reactivity in melts;

-        it will be shown that, to realize the potential of combined diamond electrodes in melts based on sodium tungstate or molybdate, access of oxygen is necessary, and that for chloride melts – excessive pressure of carbon dioxide is needed;

-        electrochemical potentials of carbon electrodes in melts of different chemical composition will be measured, their dependence on acid-base properties of the melt will be determined, and, on this base, a way to control them will be found;

-        the ability to control carbon electrode potentials will form the basis of technologies of chemical and galvanic processing of these materials;

-        theoretical basis of electrochemical synthesis of carbon nanotubes and nanorods by electrolysis of carbonate melts will be developed.

The practical significance of the results to be obtained will consist in the following:

-        conditions (melt composition, temperature, current density) for deposition of coatings of molybdenum, tungsten, and their carbides from halide-oxide and oxide electrolytes onto surface of carbon materials of different polymorphic modification and dispersion degree will be defined;

-        methods of direct chemical and electrochemical deposition of coatings of refractory metals and their carbides onto surface of carbon materials with different dispersion degree, which will allow to increase the durability and performance of abrasive tools made from these materials and to reduce their cost will be developed;

-        conditions (melt composition, temperature, density, nature and structure of carbon electrodes) for electrochemical synthesis of carbon nanotubes and nanorods by electrolysis of halide-carbonate and carbonate melts will be determined;

-        changes of physico-mechanical (strength, microhardness, abrasivity, capillarity etc.) and operational (performance) properties of dielectric carbon materials and tools after deposition onto their surface of coatings of molybdenum, tungsten and their carbides.


 

SCIENTIFIC AND TECHNICAL COOPERATION PROJECT

Open International University of Human Development «Ukraine»

Prof., doctor of technical sciences Victor Malyshev

Director of Institute of Engineering & Technology

23 Lvivs’ka St.

03115 Kyiv, Ukraine

Tel/ Fax: +38044 4249433

E-mail: victor_malyshev@mail.ru

 

Electrochemical synthesis of hard-alloy nanocomposites based on molybdenum and tungsten carbides and on iron triade metals  

 

Aims and field of the project:

The aim of the project is the theoretical backgrounding and development of the new method for high-temperature electrochemical synthesis of nanosized powders of molybdenum carbide and tungsten carbide composites as well as compositions based on molybdenum and tungsten carbides with iron triad metals from tungstate-molybdate-carbonate melts.

The project refers to the priority "New materials and technologies, nanotechnologies." Area of study is the high-temperature chemistry and electrochemistry and materials science.

One of the most important tasks in the production of hard alloys is to create tungsten-less hard alloys or to search for equivalent substitutes able to maintain high physical and mechanical properties and performance under extreme conditions. One of such substitutes could be molybdenum able to form chemical compounds similar to compounds of tungsten. Most commonly, molybdenum and tungsten are used in the form of molybdenum and tungsten carbides during the production of cutting and wear-resistant materials used in metalworking, in oil, gas and mining industry, construction industry, in electronics and electrical engineering, and also in the military-industrial complex.

The grain size of the starting material (one of the most applicable materials – tungsten carbide) and the percentage of matrix metal (Co, Fe, Ni) have a decisive influence on the physical properties of the alloy – hardness, strength, and wearing resistance. The addition of ultrafine powders to the matrix improves the properties of the standard hard alloys by changing their structural parameters. Inclusion of refractory and hard ultrafine particles into the layers of the matrix can improve resistance to wearing at elevated temperatures during high speed cutting, and, besides, create the barriers to the spread of microcracks. Due to the presence in the hard alloy structure of ultrafine powders, adhesion wearing is reduced, and wear resistance of instruments is increased 1.3 - 1.8 times over traditional hard alloys. On the other hand, the sintering of hard alloys from nanopowders and metal matrix will allow to obtain new nanostructured hard alloys, which are characterized, besides sharp increase in hardness and wearing resistance (more than 2 times), by 30-50% higher strength properties, which will expand the area of their application. Especially of high performance are products made of nanoscale, ultrafine, and submicron powders with grain size from 50 nm up to 850 nm.

Among the methods of synthesis of powders of carbides able to solve the problem of obtaining nanosized particles, high-temperature electrochemical synthesis (HTES) is very promising. HTES of dual molybdenum and tungsten carbide is based on the multielectron electrochemical processes of joint deposition of molybdenum, tungsten and carbon at the cathode with their subsequent interaction at the atomic level to form nanosized powders of dual molybdenum and tungsten carbide. This method eliminates the need for intermediate stages of preparation of starting material and thus significantly reduces the production scheme. Also, it does not require sophisticated equipment and is environmentally safe.

Basic requirements for methods of obtaining nanopowders include the ability to monitor and control process parameters, narrow particle size distribution, reproducible obtaining of powders with controlled dispersion, chemical and phase composition. High-temperature electrochemical synthesis satisfies these requirements. The main advantages of the HTES method are the possibility of synthesis of carbides nanopowders at relatively low temperatures, non-toxicity and non-hygroscopicity of components used in the synthesis of double carbides of molybdenum and tungsten, and technical simplicity of hardware design for synthesis. Since, during the high-temperature electrochemical synthesis, interaction between components of the synthesized material occurs at the atomic level, the method allows to obtain powders with high dispersion level.

Development of molybdenum and tungsten industry is defined by exceptional properties of tungsten (refractoriness, chemical, abrasive and erosion resistance, high mechanical strength and emission ability) which allow to use it in the production of high quality steel, superhard and acid-resistant alloys, carbides, borides, and special materials for many industries.

Quality products from molybdenum and tungsten carbides is mainly determined by dispersion, i.e. grain size, of initial powder from which they are made. The smaller grain size of carbide powder, the higher quality of products. Products with especially high performancies are made of nanoscale, ultrafine, and submicron powders with grain size from 50 nm up to 850 nm. Therefore, to produce high quality hard alloys and products made of them, only fine powders are used.


 

SCIENTIFIC AND TECHNICAL COOPERATION PROJECT

Open International University of Human Development «Ukraine»

Prof., doctor of technical sciences Victor Malyshev

Director of Institute of Engineering & Technology

23 Lvivs’ka St.

03115 Kyiv, Ukraine

Tel/ Fax: +38044 4249433

E-mail: victor_malyshev@mail.ru

 

Theoretical background of new ecologically safe low temperature electrolytes for realization of electrochemical processes of deposition, refining, and processing of noble metals  

 

Investigation of of chemical and electrochemical behavior of low-temperature ion-organic melts containing noble metals (Au, Ag, Pt, Pd, Rh, Ir, Ru) compounds is planned. Study of of melt structure, of electroreduction processes, of influence of electrolyte composition and the nature of metal and electrolyte properties on electroreduction, of coelectroreduction regularities of two or more noble metals with alloys formation will be done. Mechanism of and kinetics of noble metals electroreduction and electrodissolution will by studied. On of the base of established regularities, theoretical background noble metals electrodeposition as disperse powders and coatings and processing will be proposed.

General fundamental scientific problem on the decision of which project is aimed:

The purpose of the offered project is the development of long-term scientific and technical collaboration between leading scientific establishments of USA and Ukraine, having experience of solution of such complicated technological problems within areas of high temperature chemistry and electrochemistry, material technology, and also development of new competitive technologies of electrodeposition and processing of noble metals as powders and coatings.

Noble metals are among main components of hard alloys, wearing and corrosion resistant, catalytically active compounds. For today, more than 50 % of the world overall production volume of these metals are used for various coatings obtaining.

During last 20 years, literature data on the use of low(room)-temperature meltss in electrochemical studies. Before, experimental and applied electrochemistry was based on the use of water electrolytes and molten salts. Lacks of the use of the known electrolytes:

  - water-based – toxicity (CN-, F-, SO42-), low limit of current density, low speeds of electrodeposition and electrodissolution, side processes (N2 and O2 liberation), problem of waste waters;

  - high-temperature molten – high power consumption, technological difficulties (hygroscopicity, inert atmosphere necessity, need in complicated apparatus).

Indicated limitations of both types of electrolytes can be significantly neutalized in case of use of low-temperature (< 1000 °С) and, especially, room-temperature (< 250 °С) melts as electrolyte-solvent.

Chemistry and electrochemistry of low(room)-temperature melts are one of main directions in chemical science in our time. Creation of such electrolytes is possible with the use of the mixed ion-organic melts. Such mixed molten compositions are characterized by low melting temperature, high heat resistance, high conductivity, wide “electrochemical window”, and ability to dissolve metals compounds. Applications require additionally low cost of chemicals and large scales of their production.

Increased interest to the questions of development of new effective methods of obtaining of noble metals caused by their use for modern technique needs broadening continually. Comparative analysis of existing methods of obtaining and processing of noble metals has shown that one of the most prospective but still poorly studied is method of electrochemical deposition and processing in low-temperature ion-organic melts.

Electrodeposition and electrochemical processing of noble metals are based on multielectron processes of electrodeposition and electrodissolution of metals. Absence of information about theoretical background and principles of management of multielectron processes prevents carrying out practical electrodeposition. However, systematic information on the multielectron processes of electrodeposition of noble metals is accumulated in the last two decades serving as scientific background and as cause of the revival of interest to the problem of the electrochemical deposition and electrochemical processing.

Specific fundamental task addressed by project:

The purpose of this project is creation of new ecologically safe low(room)-temperature ion-organic compositions as melts-solvents for the study of electrochemical behaviour of noble metals, exposure of specific descriptions, in іон-органічних fusions and realization of processes of besieging, affinage and treatment of metals.

Project will not use described in literature low-melting electrolytes. Search for new low(room)-temperature compositions will be conducted in two ways.

I – on the base of molecular organic compounds with salts of inorganic acids for increase of their conductivity;

II –on the base of ionic form of organic compound as a solvent.

However, electrolyte composition selection is not the only problem in the solution of the stated task. As research objects, noble metals (Au, Ag, Pt, Pd, Rh, Ir, Ru) characterized by polyvalent transitions, high affinity to oxygen, and passivation, are selected. Due to this cause, investigation of their deposition and electrochemical processing is rather difficult task in experimental aspect. Therefore, for the stated purpose achievement, complex approach will be used including study of all the processes taking place during electrolysis, both electrochemical and chemical. An important role in implementation of proposed project will be played by previous experience of studies of mechanism and kinetics of electrochemical transformations being characteristic for polyvalent metals in middle-temperature (USA) and high- and low-temperature (Ukraine) melts.

Expected scientific results:

It is possible to hope that, in case of positive results, processes of obtaining, refining, and processing of metals will be practically realized due to study objects choice, production of which is of interest for different countries of Europe and USA, as analysis of literature sources shows.

Transition to low-temperature melts from high-temperature electrochemistry will provide obtaining of economic advantages due to decrease of power consumption, to simplification of technology, and to use of cheap chemicals. Also, it will improve accident prevention and environment protection levels.

Joint publications, presentations at international conferences, patents, workshops are provided for by the project. Investigatuions results will be used for preparation of joint master's degree programs with supervision from both countries-partners sides. Obtained results will be presented in international chemical and materials science journals, at conferences on ionic melts and ecological monitoring. Lectures and practical lessons are planned for students and employees of both institutes-partners. Patenting, transmission of technologies to third parties, protection of intellectual property will be carried out to in compliance with the legislation of the Ukraine and of the USA.

Novelty and development state estimation:

Scientific novelty of the results to be obtained will consists in the following:

1. Establishment of mechanism of formation and subsequent reduction of compounds of noble metals in low-temperature electrolytes of different nature

2. Study of phase formation during the electrodeposition of noble metals depending on electrode material and conditions of deposition (temperature, parameters of electric current).

3. Establishment of mechanisms of anode dissolution of noble metals depending on nature of ion-organic melt and metal, and also on conditions of dissolution.

The practical value of the results obtained consists in the following:

1. Obtaining of competitive catalysts on the base of noble metals in the reactions of inorganic and organic synthesis in comparison with existing ones.

2. Possibility of considerable increase of superficial hardness, wearing and abrasion resistivity of steel construction materials.

3. Possibility of considerable increase of corrosion resistivity of steel construction materials in acid solutions and molten electrolytes.

4. Possibility of obtaining of intermetallides on the basis of noble metals of preset composition both as powders and as coatings on construction materials.

Implementation of scientific and practical tasks is interrelated, and they are implemented simultaneously. Their symbiosis will be useful in achievement of purpose of collaboration. Importance of project for both partners needs close mutually beneficial collaboration.


 

Open International University of Human Development 'Ukraine'

Mykola Monastуrov

Director of Research Institute of Ecology and Alternative Energy

E-mail:  newtec@list.ru

mob. phone +38067 243 24 14

Field of research

Scientific developments ready for implementation

1.

Ecology 

Domestic wastewater and industrial water of any kind and level of pollution

Intensive depletion of reserves of clean fresh water caused by the increasing pollution of water sources by industrial and domestic effluents and their progressive salinization. Therefore there is an important problem of preventing the flow of harmful substances and salts in natural waterways and drains. This problem is related to global environmental issues and demands the immediate and effective solutions. Otherwise clean fresh water can be classified as limited natural resources.

After analyzing the main types of water contamination, classical and modern methods of cleaning and test them in practice were developed efficient algorithms for water quality management.

Research priorities in developing technologies were physical and chemical-free methods of influencing the contaminated water, which minimizes the probability of synthesis of new compounds and do not increase the amount of precipitation received.

The main criteria influencing the processes of research and design were:

— Ensuring synergies during equipment exploitation;

— Energy efficiency and depth of water purification;

— Easy to input parameters of water;

— Flow cleaning mode;

— Compact and autonomous operation of the equipment;

— Low maintenance.

Developed conceptual units have a modular design. This allows you to create a unified range of equipment that entails a reduction in the cost of products. To verify the technology in practice as an experiment have been cleared:

—    sea water of Azov Sea to the level of drinking water according to Ukrainian national sanitary norms;

—    electroplating wastewater engineering plant: the degree of heavy metal ions from the electrolyte (ions Cu, Cr+6, Al, Zn, Cd, Fe, Ni, Pb, Sn) extraction was 99,9 %;

—    sewage collector central Kiev (Ukraine): were decontaminated in the flow regime on the level of presence of coliform bacteria 24×1011/l to almost 0;

—    tobacco factory «Imperial Tobacco Production Ukraine» wastewater (Britain, Germany): the concentration of harmful substances reduced 5÷150;

—    underground landfill filtrate from number 5 city solid waste dump to the level of standards to the wastewater for discharge to sewage;

—acidic runoff of area for products of diamond synthesis enrichment (State Enterprise «Alkon-Diamant», Kiev ) —

    up to sanitary standards for wastewater discharge to sawage;

—    underground mine water Donbass region, Ukraine — to the level of ultra-pure water for high-tech industries);

—    purification of radioactive isotopes model solutions — complete cleaning;

—    electroplating wastewater plant «Zorya-Mashproekt» (Nikolaev, Ukraine) — up to sanitary standards for wastewater discharge into the sewer;

—    For selecting the technology for wastewater treatment is determined the nature and level of their pollution and required depth of cleaning. For each type of pollution recommended most technically and economically efficient technologies.

 

2.

Ecology

High-tech systems for drinking water treatment

Equipment for drinking water treatment series NIAGARA® is a modern, highly efficient and multifunctional complex, which is capable to fully disinfection and purification of water from excess iron, mangan, salts of heavy metals, phenols, chlorinated organics, hydrogen sulfide, nitrogen containing compounds, synthetic detergents, petroleum products, and to improvement of the organoleptic indicators of water, etc.

Ozonation is the most efficient and environmentally safe of all existing technologies, because it does not use any chemical reagents.

This technology purifies and disinfects the water deeply and effectively and in doing this it retains all it's useful and biologically important minerals and microelements for human beings (potassium, calcium, magnesium, iodine, bromine etc.).

The quality of drinking water meets the high standards of sanitary SanPiN to the drinking water and regulations of the State Standard of Ukraine 4808.2007.

This water has the taste of the mineral source, and it is an unattainable goal if we are using other methods.

In the process of working, the water passes through the stages of magnetic treatment, ionic saturation by silver and filtering. Intermediate toxic and cancerogenic compounds do not appear on the completion of the process.

The degree of readiness of the project to the implementation

Technology and a wide range of installations (8 blocks) for water ozonation with stabilization of the bacterial situation with the help of ionic silver and automated process of management system was worked out. 

The research results and the effectiveness of technology were verified at the National Academy of Medical Sciences of Ukraine and the schools of the Ministry of Health Care of Ukraine.

Technical conditions of Ukraine 31.6-30373644-001:2011 were worked out and approved. The production was certified in the UkrSEPRO.

Technology of ozone treatment of drinking water is ready to start its mass production. Implementation of the water systems of the series "NIAGARA ® has great moral and economic effect.

The availability of high-tech engineering systems of water treatment in the houses and office buildings has to maintain high sanitary standards (clean drinking water in taps) that will ensure the liquidity of housing and office space, as well as the overall health of the nation.

It is obviously that the last factor has a positive impact on the economy of the country.

 

3.

Ecology

Technologies for air purification from organic and inorganic contaminants, disinfection and deodorization

«NEWTECfreshbreeze » technologies of electrostatic and ozone treatments of air purification from organic and inorganic contaminants and its disinfection and deodorization are modern and highly effective methods.

The main advantage of the technologies is their unprecedented efficiency, full ecological purity and versatility, as well as the lack of chemical reagents, small quantity of the process stages and compact equipment.

«NEWTECfreshbreeze» technologies had passed the multiple field tests on the technological buildings of Bortnitskaya aeration station (Kiev) under the supervision of the Institute of Hygiene and Medical Ecology named after O.M. Marzeyev in the National Academy of Medical Sciences of Ukraine. According to the records of the Institute No. 20/6289 from 16.11.07 and 20/5633 from 02.11.2011, the efficiency of suppression of harmful ejections of hydrogen sulfide, ammonia, methyl marcaptan and methane reaches 98÷100%.

Application of the technology of ozonation in medical establishments will greatly reduce the risks of germicidal infecting of the population and terrain and prevent outbreaks of viral diseases in the industrial enterprises, houses, etc.

 

4.

Energy  

Energy efficient electric electrode system of the local heating

Economic practicability forces entrepreneurs to refuse from central heating in favor of the individual heating.  

The system of individual heating allows to:

adjust the temperature in the room at the request of the consumer, on the basis of  individual imagination of comfort  and economization;

automatically maintain a desired temperature indoors;

integrate electrode heaters in the system «Smart House»;

lower the room temperature in the absence of people there for a long time;

give the consumer the opportunity to make a decision regarding the start and end of the heating season personally.

    Electronic heater is not constantly working device. Its function is in automatical supporting of the assigned  temperature through the compensations of heat losses. Therefore,

     a quantity of electric energy used is directly proportional to the heat losses of the accommodation.

The initial capital costs and expenses on the maintenance of the installation of the electrode heater can fall in proportion between a number of adjacent users in the case of the installation of multi-access electrode heater (on the floor, standpipe of the entrance, separate House, etc.).

Electrode heaters are in one price niche with the electrical heaters of analogous intensity.

Their advantage lies in the technical and operational characteristics, namely:

high operational reliability occurs due to the direct flow of electric current in the heat-transfer agent;   

«soft» control characteristic (absence of the splashes of the starting current);

no penetration of reverse idler harmonics, which can lead to failure of one or other electric users in the network;

automatic smooth output at full capacity;

complete fire safety in case of decompression of the system (the heating system stops its work automatically if the heater leaks);

significant savings in electricity consumption (up 32%) because of the direct heating of the heater and programmed management;

term of operation of the electrode heaters is determined by an electrochemical corrosion of metal only and it is not less than 20 years;

ability to use it as a secondary heat source in combined heating systems;

the ability to create local heating system;

the high accuracy of control and support of the assigned temperature;

high coefficient of energy conversion (close to 1).

The many-year experience of the operation of electrode heaters showed that at the temperature of the external wind up to -15о С for supporting of the internal temperature at +20÷21о С the installation works 5÷7 hours per day.

The degree of readiness of the project to the implementation.

The design of single-phase and three-phase electro-electrode heaters was worked out.

The technical conditions of Technical Specifications of Ukraine 29.7-37639343-001:2011 are worked out. Products are certified in UkrSEPRO.

The availability of high-tech engineering constructions with features of supporting sanitary standards of high level (comfort heat) in office buildings will ensure the liquidity of housing and office space as well as the general health of the population.   

The latter factor will definitely have positive effect on the economy of the country.

A wide range of structures of boiler and thermal points (38 units) on the basis of electrode heaters with heat exchangers and automatic control system is developed.

Efficiency and technical parameters of the heaters are verified.

The design documentation with its own decimal code is prepared.

 

5.

Nanotechnologies 

Getting of submicron and nano disperse metal powders

A new industrial technology to large-scale production of powder materials by means of electro - erosion dispersing of metals and their alloys was developed.

Due to the fact that the developed method has great technological capabilities, there is a real opportunity to help consumers of powder materials solve their problems concerning the quality and nomenclature of such materials.

The method of еlectro-erosion and dispersion (EED) is in receiving of submicron and nano disperse metal particles by means of the impact on the granules of powerful electric discharges.

This method allows you to disperse any electro-conductive materials without using heat-resistant equipment.

However, the indicated method allows to enter into the crystalline grates of particles of having been obtained metals any admixtures, and also gives the possibility of obtaining the powders of spherical form with amorphous, similar to glass and in small crystal structure of particles with the highly developed surface (unique magnetic properties, the highest chemical activity, sorption ability, etc).

The size of the particles of metal (alloy) with different characteristics of discharges and modes of operation of the reactor is from 2 nm to 7 microns.

Theoretically, at corresponding parameters of electrical discharges with the help the electro-erosion dispersion method (EED) it is possible to obtain the smallest particles, up to the atomic level.

The process of dispersing in this mode can be compared with evaporation and condensation of the metal.

But in practice it is impossible to obtain powders by the sizes <1-3 nm because the processes of creation of inter atomic connections in them flow on a very high-rate and the particles grow rapidly and convert into the conglomerations.

But in practice to obtain powders by the sizes

If the metal possessing sufficiently high chemical activity but the working situation is not also inert (water, nitrogen, hydrocarbons, etc.) is dispersed into particles to size of 3÷5 micron so the oxides, nitrides or carbides of metals can be synthesized in the process of dispersion. Such particles can have porous or monolithic structure.

Thus, for instance, the value of specific surface area for the oxide of aluminum is achieved to 700 m2/g and for zinc oxide to 120 m2/g.

The chemical activity of the oxide of lead, which was obtained by EED method exceeds the action of the powder of oxide of lead, having been obtained on a round mill, in 4÷7 times.

The reagents capable to pollute the environment are not used for obtaining the powders.

The chemical cleanness of having been obtained products corresponds to the chemical cleanness of feedstock.

EED method is the most competitive in those cases, when the powders of high quality are required (especially small, ultrapure with the highly developed surface etc.) and also, in case of processing of metals with extreme physical and chemical properties (hardness, plasticity, brittleness, toxicity, refractoriness, chemical activity, etc.).