Design of a Multilevel Structure of Diamond-Matrix Interface Boundaries and its Role in Increasing the Durability of Diamond/Hard-Alloy Composites

摘要

Increasing the processing speeds and expanding the range of processed materials lead to the need of improving the durability of composite diamond materials used as working elements of diamond tools. To improve chemical and mechanical adhesion of natural diamond particles to a hard-alloy matrix, a hybrid technology is proposed, which combines thermal diffusion metallization of diamond and sintering according to an original scheme of self-dosed impregnation with a low-melting metal in a one-stage technological cycle. The aim of this paper is to study the boundaries between the diamond and the matrix in diamond composites produced according to the new technology and the main factors determining the durability of a diamond tool in the presence of a metallized coating. Structural and phase arrangement, distribution of reaction products, and structural forms of carbon (diamond and graphite) in the diamond-matrix contact zone of diamond tool prototypes are investigated by scanning electron microscopy, X-ray diffraction analysis and Raman spectroscopy. The formation of a fine-structured transition layer with the multilevel arrangement of morphological elements, which ensures the monolithic character and strength of the joint between the diamond and matrix, has been revealed. The improvement of diamond retention increases the specific productivity of experimental tools by 39-45%.