Work

The work deals with the solution of a science and technology problem of producing the wear resistant polycrystalline diamond composites using the established regularities of high-pressure sintering of diamond powders of two degrees of dispersion and determination of the prerequisites to the formation of tungsten carbide particles, which are chemically bonded with diamond, between diamond nanoparticles and make possible the thermostability improvement of produced composite. The surface treatment effect on the nature of the compaction of diamond powders of different geneses and dispersions of two degrees and of their mixtures with sintering aids during the precompaction at room temperature have been studied as well as the influence of the vacuum treatment, high pressures and temperatures on the sintering processes. Based on the results of these studies, a diamond–tungsten carbide composite material was developed and its optimum composition, structure, production parameters, physico-mechanical properties have been defined as well as operational characteristics of drilling tool working elements made of this composite material. The composite has the structure, in which the tungsten carbide and diamond grains are regularly placed and are uniform in size. The composite combines high hardness (at 1100 оС HK = 25 GPa), thermostability (КТS = 0.86), and fracture toughness (KIc = 6.6 MPa·m1/2). High values of wear resistance of composite diamond - tungsten carbide based on diamond powder of two levels of dispersion are reached due to the choice of optimum additive content, as well as by the addition of large diamond particles. Conservation of large particles in the structure of polycrystalline diamond composite, by other equal conditions, improves its durability 2-3 times. The best selection of proposed components and parameters sintering provides a persistent connection metal layers and polycrystalline diamond composites directly during sintering of polycrystalline diamond composites. The simultaneous sintering and metallization of composite provides an economic advantage, which is to reduce the number of manufacturing operations. The experimental-industrial test of working results has shown that the developed diamond – tungsten carbide polycrystalline composite material is effective for the use in drilling tools. Series of studies were carried out during 2006 - beginning 2015 in V. N. Bakul Institute for Superhard Materials of the National Academy of Science of Ukraine. The series consist of 20 publications, among them - 16 articles, 15 of them in professional journals of Higher Attestation Commission of Ukraine, 4 in refereed journals, 2 patents of Ukraine for device and 2 patents of Ukraine for useful model were obtained.