Features of the Structural-Phase State of the Diamond-Matrix Boundary Zone in Diamond-Containing Composite Materials

Abstract

Preliminary metallization of the diamond component, which promotes the formation of chemical bonds on the diamond-matrix contact during subsequent sintering, is used to increase the strength of diamond retention and the durability of diamond-containing metal matrix composites. There are restrictions on carrying out metallization to create diamond composites with a cemented carbide matrix, since reheating the metallized coating at high sintering temperatures of carbide powders leads to its destruction, diamond graphitization and deterioration of the material properties. The structural-phase state in the diamond-matrix contact zone has been studied and the main factors providing the strength of diamond retention in diamond-cemented carbide composites obtained by hybrid technology that excludes the reheating of the metallized coating have been revealed. It was revealed, that the developed hybrid technology combining the thermal diffusion metallization of diamond and sintering according to the self-dosed impregnation scheme in one cycle ensures the production and preservation of the metallized coating by the methods of scanning electron microscopy, X-ray diffraction and X-ray phase analysis, Raman spectroscopy. Comparative tests have been carried out and it is shown that the specific productivity of experimental samples of a diamond tool (ruling pencils) with a metallized diamond component is on 39% higher than same parameter of pencils without metallization.