Roman S. Regularities of structure and prpoerties formation of the diamond composites with multicomponent Ni-Sn based binder by intensive electrosintering

Dissertation for the candidate of technical sciences degree in speciality 05.02.01 - Materials Science. - V. M. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine.The thesis deals with the patterns of structure and properties formation of the diamond composite materials (DCM) with multicomponent Ni-Sn based binder by the intensive electrosintering (IES). It has been shown that IES is a promising method of DCM production which provides full consolidation of green compact in tens of seconds while preserving initial quality of diamonds. The leading mechanisms of DCM densification by IES involve termally activated plastic deformation of nickel powder particles, tin melting and mass transfer and chemical interaction of the bond components. The regularities of the multicomponent systems IES under pressure in presence of liquid phase have been explored. The presence of a liquid phase during the electrosintering increases conductivity of green compact and intensity of heating which, in turn, significantly increases the shrinkage rate and promotes uniform distribution of components and formation of intermetallic compounds. The macrokinetic model of intermetallic compounds formation in the system Ni-Sn under non-isothermal conditions has been developed. The effect of the powder mixture on the microstructure formation and physical and mechanical properties of DCM has been studied. The promising in terms of DCM quality technological parameters of IES have been established. The proposed energy-efficient method of manufacturing the drilling crowns constitutes a prototype of the new industrial production technology of diamond tools. Keywords: diamond composite material, intensive electrosintering, multicomponent bond, intermetallic, thermal conductivity, hardness, drilling bit.