Diamond Glasses and Composites Production by Means of High-Pressure-High-Temperature Treatment
Tech Area / Field
- MAT-SYN/Materials Synthesis and Processing/Materials
3 Approved without Funding
Technological Institute of Super-Hard and New Carbon Materials, Russia, Moscow reg., Troitsk
- NPO Soyuz (2), Russia, Moscow reg., Dzerzhinsky\nNPO Lutch, Russia, Moscow reg., Podolsk\nMISIS (Steel and Alloys), Russia, Moscow
- Texas Technical University / Department of Mechanical Engineering, USA, TX, Lubbock\nTechnische Universität Ilmenau, Germany, Ilmenau\nUmeä University, Sweden, Umeä
Project summaryNanocomposite diamond materials (diamond glasses) attract considerable attention because of two major reasons:
1. The task of the nanocomposites manufacture is tightly connected with the task of utilization of explosives and missile hard fuels (MHF), which have limited storage time and should be demolished until it is over. This requires extra costs and threatens the environment. Ecologically clean and safe technology of ultrafine (20 angstrom and larger) diamond powders production from explosives and MFH was developed recently. It is considered to be one of the best solutions of the problem. The explosives and MFHs are detonated in closed chamber, so environment is protected. Ultrafine diamond powders were found beneficial for special plastics, for varnishes and dyes, for improved lubricants, etc., medical applicability is under investigation now.
2. “Nanostructured materials” is modern trend in materials science. It is known that top strength and hardness (comparable to shear modulus value) could be obtained in two marginal cases. If a solid is perfect single crystal (without structural defects), or if a solid consists if ultrafine grains tightly bonded with each other. For example the hardness of diamond single crystals ranges from 80 to 140 GPa (connected to quality), while for nanocomposite diamond materials it reasonable to expect hardness Gdiamond ~ 450 GPa. Weibull modulus (that characterize homogeneity of a material) for the synthetic diamonds ranges from 1.2 to 2.5, while for diamond nanocomposites it could reach 10 and higher values. X-ray patterns for such materials comprise very broad peaks that indicate high structural disorder typical for glass-like structures.
Therefore nanomaterials produced from ultrafine powders (diamond glasses) are expected to be superior to existing diamond polycrystals or compacts, and have higher values of elastic modulus, strength, hardness and wear resistance. The isotropy of properties should be higher also.
Industrial application of these materials seems to be quite promising if we consider smooth machining (cutting tools for finishing and high finishing), stone-working, mining operations. The task of production of high-strength material from ultrafine diamond powders (UFD) not been solved so far. Numerous attempts to produce double-layer-cutting tools (diamond plus hard alloy) have not achieved desirable result.
Prospects and tasks described above necessitate investigation in the field of glass-like nanocomposites and ultrafine diamond powders. The investigation tasks are along side to the task of explosives recycling and of ultrafine diamond powders utilization, which are rather cheap and available in quite big amount. It makes necessary analytical equipment elaboration to carry out investigations of new materials properties as well as new technologies development to produce these new materials.
Objectives of the project are the following:
1. Recycling of missile hard fuels and explosives, their transformation into ultrafine diamond powders (UFD).
2. Mass production of UFD in quantities sufficient for the project elaboration, i.e. for production of diamond nanocomposite materials with outstanding mechanical properties.
3. Development of technological approaches for secondary recycling of products of explosives and missile hard fuel recycling into high-tec products.
4. Manufacture of glass-like UFD nanocomposites with the following properties: density not less than 98% of diamond density; hardness 90-110 GPa; compressive strength not less than 4 GPa; heat conductivity 400-600 W*m/K.
5. Manufacture of double-layer (nanocomposite layer plus tungsten carbide or titanium carbide layer) cutting tool inserts with diameter up to 13 mm.
Scope of the project (The ways of the project elaboration):
1. Perfection of the technological equipment for starting and final materials production. Development of the investigation techniques for new materials properties investigation.
2. Investigation of consolidation into glass-like final state (under high-pressure-high-temperature conditions) of starting mixture of nanoparticles and ultrafine diamonds.
3. Development of technological approach for diamond glasses production from ultrafine diamond powders with high-pressure-high-pressure treatment.
4. Production of nanocomposite diamond materials that have superior physical and mechanical properties.
Recommendations for the new materials production technology for will be summarized at final stage of the project.
The essence of the work. It is supposed that superhard materials of new generation will be produced as the result of the project elaboration. The materials will have higher physical and mechanical properties than recent materials.
The materials will be obtained by means of treatment under high static pressure and temperature 1300-2000 °C of ultrafine diamonds and nanosized non-diamond particles.
The project includes the following subtasks:
- Perfection of existing technology of ultrafine diamonds production when explosives, hard missile fuels and highly toxic substances are used as raw materials.
- Development of the methods of homogenous mixtures creation where non-diamond part amounts to 0.58 %(mass).
- Perfection of high pressure equipment used for superhard materials production.
- Development of measurement means and techniques to investigate mechanical properties of glass-like superhard materials.
- Investigation of consolidation mechanisms that act in reaction system that comprises ultrafine diamonds and particles.
- Production of the samples of glass-like composite diamond materials, their properties investigation.
- Collection of the recommendations for industrial technologies of new diamond composites and UFD cutting tool production.
Novelty of the work proposed includes the following. Considerable amount of explosives will be utilized wasteless for the purpose of new materials creation. Investigations will be carried out for the first time on consolidation mechanisms acting in multiphase system of nanoparticles that were produced by means of direct blasts of explosives or hard missile fuels. Original techniques of staring materials manufacture and pretreatment will be created. High-pressure-high-pressure sintering techniques for glass-like nanocomposites production and special investigation techniques to test the materials mechanical properties will be developed.
New nanocomposite materials and production methods are highly competitive. New materials creation in general and nanostructured materials creation in particular is considered to be key direction of word material science.
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