Recommended application field: Tools made of the composites of statically synthesized diamond nanopowder can successfully compete with singlecrystal natural diamond tools. The composites may be used for making cutting, deforming or measuring tools for various purposes. Due to high fracture toughness, they may be also used as inserts in drilling tools.Now the samples of the instrument are being tested in construction.

Advantages over analogues: It is experimetally proved that the most efficient approach to improvement of physico-mechanical properties of diamond polycrystals produced from nanopowders is to find optimal conditions for sintering of mixstures containing additions acting as solvets for carbon (Co, Ni, alloys of them, etc.) and as inhibiters of the grain growth. The mixture should be mechanically activated. The use of high-pressure technique in combination with purification and vacuum degassing for sintering of statically synthesized diamond nanopowders with an initial particle size of about 100 nm favors the formation of nanostructure elements of 10 to 50 nm in a polycrystal due to fragmentation of coarser initial grains (superted by TEM studies). Preactivation of the initial statically synthesized diamond nanopowders using cold isostatic pressing has allowed the production of polycrystals with a density of 3,31 g/cm3, Vickers hardness of 35 GPa (P=9.8 N) and fracture toughness K[1c] = 10-14 Mpa.m(1/2).

The development stage readiness: Tested experimental exploitation order

Description of the development:
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At present one of the most important directions in solving the problem of superhard materials development with qualitatively and quantitatively new complex of physico-mechanical properties is the use of nanodispersed materials as the initial ones. Under adequate conditions a unique conplex of mechanical properties, e.g., a combination of very high hardness and fracture toughness, can be realized in a nanodispersed polycrystal. In development of production technologies of novel superhard materials using initial nanomaterials, retention of the material nanodispersed state in the course of sinterling is an important problem. In addition, one should remember that mechanical properties are highly structure-sensitive, which is particularly distinct in using nanomaterials. Conditions of preparative treatment of diamond nanopowders, and their effective compacting, before a sintering including at heightened temperature, have been developed. Effect of prior compacting conditions on process of obtaining of qualitative polycrystals by sintering has been studied. Thermobaric conditions of production of nanometric range have been investigated and optimized. The obtained results have allowed to develop optimum conditions of tool materials based on the diamond nanopowders production.

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Country Ukraine

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E-mail: gal@uintei.kiev.ua