Study of the Composition Influence of Composites Based on Sintered Impact Diamond on their Wear Resistance during Processing of Silicon Carbide

Abstract

The article presents the results of comparative tests on the wear resistance of composite materials (CM) sintered at high pressures and temperatures based on impact diamond (diamond-lonsdaleite abrasive — DLA) when processing silicon carbide (SiC). To assess the CM performance based on impact diamonds, a method has been developed for determining the wear resistance, based on the determination of the CM specific productivity. It is shown that for CMs based on impact diamond, it is expedient to use SiC as a binder. For CMs based on impact diamond with an additive of 40 vol.% SiC, specific productivity when machining a silicon carbide wheel is 25–30 % higher than for compositions containing dense BN phases — wBN and cBN. The decrease in the specific productivity of CM “impact diamond — cBN” relative to CM “impact diamond — SiC” is determined by the higher dispersion of crystals of dense BN phases in comparison with SiC, which generally impairs the abrasive ability of the material. In this case, the addition of a coarse fraction of impact diamond 100/63 μm to the charge composition does not lead to an increase in the specific productivity of the abrasive element as compared to CM based on DLA with a particle size of less than 40 μm. Preliminary mechanical activation of the initial charge also reduces the CM abrasive ability due to the formation of a highly dispersed structure of the material.

Keywords

• impact diamonds
• high pressure and temperature
• sintering
• silicon carbide
• cubic boron nitride
• wear resistance