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Synthesis of Diamond Glass

#2640


Synthesis of Nanocomposite Materials on the Basis of Ultra Disperse Diamonds and Nano-Size Non-Diamond Carbon Structure Oxides and Carbonates of Metals

Tech Area / Field

  • MAT-COM/Composites/Materials

Status
3 Approved without Funding

Registration date
12.11.2002

Leading Institute
Technological Institute of Super-Hard and New Carbon Materials, Russia, Moscow reg., Troitsk

Supporting institutes

  • VNIITF, Russia, Chelyabinsk reg., Snezhinsk\nMISIS (Steel and Alloys), Russia, Moscow

Collaborators

  • Texas Technical University / Department of Mechanical Engineering, USA, TX, Lubbock

Project summary

Compact nanocomposite diamond materials attract considerable attention due to the following reason. Because of high density of inner bounds and dislocations, these materials must exceed the currently existing diamond polycrystals and compacts in hardness, resistance, wear and properties isotropy. On the X-ray pictures of nanomaterials one can see the fuzzy lines being an evidence of strong structure disordering specific for glass-like state.

The use of these materials in metal-working, specially for clean and mirror turning, stone working and mineral products mining, as well as in machine-building industry seems to be very advanced and having prospects. This task has been set since the beginning of ultrafine diamond powders (UFDP) production. However, the idea of production of monolithic high-strength materials based on UFDP has not been yet implemented in practice due to some physical and chemical problems concerning high inertia of diamond particles and their graphitization during the high-energy treatment. The numerous attempts to produce the compact ultrafine diamond samples using different methods, such as vapor-phase deposition, detonation sintering under the high pressure has not led to the expected results.

The compact material obtained using the first two methods has either the polyphase discontinuous structure or plenty of cracks.

During the sintering of UFDP under the high static pressure the powders consolidated via the carbon diffusion on the interfaces. However, this was accompanied by the fast (“blowing”) recrystallization of UFDP. This led to the compact consisted of a micron-sized grains and its properties were far from the expected ones. When sintering parameters were reduced (in order to reduce the velocity of recrystallization) the vacancies in the UFDP particles faintly migrated to the particle bounds but formed vacancy associations. These associations arranged parallel to the particles bounds and considerably worsened the compact material properties. The use of metallic or carbide couplers did not solve the problems described.

It is evident that the conventional sintering methods based on the well-known diffusion processes are not applicable for this task. One should consider other less investigated processes that take place in reacting environment of ultrafine and nanosized particles.

The described problem can be solved by adding new components to the UFD powders (elements or compounds) that would suppress the UFD recrystallization and at the same time reduce the particles surface energy to ease vacancies output and annihilation. In particular, nanosized non-diamond carbon structures, metal oxides and carbonates can act in such a way under the certain thermodynamics conditions. This represents a fundamental difference of the proposed method from the conventional sintering under the pressure using the commonly used couplers – metals and/or metal carbides.

To ensure the required nanocomposite materials properties the non-diamond composite compounds should take up minimum volume and react on the surface of UFDP to form new phases and compounds.

The described outlook makes relevant investigations in the field of nanocomposites production methods based on the ultrafine diamond powders, as well as development of analytical base for research of their properties and performance investigation. Besides, the important practical task is the use of relatively cheap and available in big amounts raw diamond materials for production of instrumental and construction materials.

Project objectives:

- Investigation of the consolidation processes in a reacting system of nanoparticles and ultrafine diamonds in the environment of high static pressure and temperature.


- Development of nanocomposites production techniques based on the ultrafine diamonds.
- Development and updating of equipment used for manufacturing these materials and of the analytical base for the investigation of their properties.
- Production of nanocomposite diamond materials having unique physical and mechanical properties.
- Recommendations concerning the development of industrial technologies for producing such materials.

The content of the work. It is supposed that superhard materials of new generation will be produced as a result of the project implementation. These materials will have the superior physical and mechanical properties. During the project both fundamental and application problems of new nanocomposite materials creation using the cumulative experimental data and already developed techniques will be solved. During the fundamental research the new information about the interaction between ultrafine, nanosized particles and nanoclusters of different composition under high pressure in reactive environment will be obtained. This is one of the key directions of nonstructures investigation and nanotechnologies development. New data about elastic, strength and thermal properties of nanocomposite materials based on the ultrafine diamonds will be obtained. In the field of application research the known experimental techniques of new materials synthesis will be improved and new techniques will be developed. The optimum thermodynamics parameters of synthesis will be evaluated. The most advanced types of new nanocomposite materials and areas of their possible application will be defined. The results of this work will allow creating in the future the experimental production technology and further application of these materials in economics.

The materials will be obtained from ultrafine diamond powders and nanosized non-diamond particles by means of consolidation under high static pressure and temperature of 1300-2000 °C.

For that purpose it is planned to fulfill the following subtasks:

- Improve the existing ultrafine diamonds manufacturing techniques, especially the purification process.


- Develop methods of homogenous mixtures creation where non-diamond part amounts to 0.5-8% (mass).
- Improve high pressure equipment used for superhard materials production.
- Develop measuring instrumentation and techniques to investigate mechanical properties of superhard materials.
- Investigate consolidation mechanisms acting in reaction system that comprises ultrafine diamonds and nanoparticles.
- Produce samples of composite diamond materials, investigate their properties.
- Develop recommendations for industrial technologies of production of new superhard diamond composites based on the ultrafine diamonds.

Novelty of the work proposed includes the following. Consolidation mechanisms acting in multiphase system of nanoparticles will be investigated. Original techniques of such system manufacturing will be created. The equipment for production and verification of composite materials will be developed. The materials with new unique properties will be produced. New nanocomposite materials and production methods are highly competitive. Creating of new materials in general and, in particular, of nanostructured ones is considered to be a key direction in the modern material engineering all over the world.


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