Structure of a Diamond–Matrix Interface and Durability of a Diamond Tool Fabricated by the Metallization of Diamond with Chromium during Sintering of the WC–Co Briquette with Copper Impregnation

Abstract

The structure, as well as the elemental and phase compositions of the diamond–matrix interface of a diamond tool for abrasive wheel dressing, manufactured using a new hybrid technology, are studied. This technology combines the thermodiffusion metallization of diamond with chromium and sintering of a matrix based on a WC–6%Co carbide powder mixture with copper impregnation in a single cycle of the vacuum furnace operation. During matrix sintering, the compact arrangement of chromium powder particles around the diamond grains and the screening effect of the copper foil form favorable conditions that ensure the thermodiffusion metallization of diamond. Scanning electron microscopy, electron probe microanalysis, X-ray phase analysis, and Raman spectroscopy show that a metallized coating chemically bound with diamond is formed on the diamond surface in temperature-temporal modes and sintering conditions. The coating consists of chromium carbide and a solid solution of cobalt in chromium, which provides durable diamond retention in the copper-impregnated carbide matrix. Herewith, the matrix structure and microhardness, excluding the regions adjoining the diamond–matrix interface, remain the same as a matrix of a carbide powder mixture sintered in the absence of chromium. Comparative tests of similar diamond dressers show the high efficiency of the hybrid technology of formation of diamond-containing composites for tool application. It is shown that the specific productivity of a dresser prototype fabricated using the hybrid technology was 51.50 cm3/mg when dressing a grinding wheel made of green silicon carbide, which is 44.66% larger than a similar indicator of the same type of check dresser formed using the traditional method.