Matviichuk O. Regularities of gas-phase WO3 carburization to WC carbide in the quaternary W-C-H-O system and structure formation during sintering of wear-resistant composites from it

As a result of the work, the actual scientific and technical problem was solved, which consists in constructing of the diagram quaternary W-C-H-O system on the basis of determining the equilibrium of chemical reactions in this system, and improving on its basis the methods for producing WC tungsten carbide powders by gas phase carburization without impurities W, W2C or free carbon by establishing an area where WC exists in equilibrium with the gas medium. It is shown that due to the significant inhibition of the external diffusion of methane, the medium-grained WC powders are most suitable for production by direct carbonization of WO3 in an open reactor and super-grained - in a two-stage method, which involves the reduction of WO3 by hydrogen or a methane-hydrogen mixture to W in a closed reactor and the gas-phase carbonization of the obtained tungsten powder is carried out at a temperature of 2300 ° C in an open reactor. Advanced technologies for the preparation of mixtures of medium-grained WC with metal binder and super-grained WC tungsten carbide powders with particle size up to 200 mkm were implemented on SSPE "Alcon-tverdosplav" on the basis of theoretical and experimental researches developed. The super-grained (> 50 ?m) WC powder obtained by gas-phase carbonization was used to study its interaction with cobalt and tungsten-cobalt melt at forming hard-alloy microstructure; as a wear-resistant filler in diamond drill bit, which resulted in increased drilling efficiency, which was confirmed by a technical test certificate.