EFFECT OF THE DIAMOND-METAL BINDER INTERFACE ON THE THERMAL EXPANSION COEFFICIENT AND WEAR RESISTANCE OF ELECTROSINTED DIAMOND COMPOSITES

Abstract

The micromechanical model of a composite with an imperfect interface is developed. It considers the effect of the degree of imperfection of the diamond-metal interface on the coefficient of thermal expansion (CTE) and wear resistance of the diamond composite. The interphase boundary is modeled by the corresponding contact conditions at the interface and the elastic-mechanical constants of the phase materials are determined experimentally or from theoretical models of the lowest level. The obtained theoretical data were experimentally confirmed for the samples of composites produced by electrosintering method on a NiSn(6%) bond with inclusions of synthetic diamonds with different types of coatings and without coating. This model can evaluate the effect of the contact elasticity of the interface and the size of the inclusions on the CTE. It exhibits that the mechanical covering of chromium to diamond grains leads to an increase of CTE and wear resistance of diamond composites of this class, due to a better interfacial contact