Combined effect of CrB2 micropowder and VN nanopowder on the strength and wear resistance of Fe–Cu–Ni–Sn matrix diamond composites

Abstract

The paper presents research results on the enhancement of diamond composites designed for tools application for mining industry, hard rocks cutting, able to withstand harsh conditions under heavy dynamical loads. In the present study, both CrB2 micropowder and VN nanopowder additives were used in proportions up to 5 wt.% and 6 wt.%, respectively, together with the basic matrix composition of 51 wt.% Fe, 32 wt.% Cu, 9 wt.% Ni, and 8 wt.% Sn. Addition of both components, CrB2 and VN, appeared to be advantageous in proportion of 2 wt.% and 4 wt.%, respectively. This composition exhibited the highest relative density of 0.9968, better than that without additives. Similarly, the highest values of compressive strength Rcm and flexural strength Rbm were reached for the composite with the same percentage of CrB2 and VN. Compared to the composite with no addition of CrB2 and VN, Rcm im-proved by almost 70%, while Rbm by 81%. Additionally, the abovementioned additives enhanced the ability of the matrix to prevent the diamond reinforcement from being torn out of the composite, which is very important under harsh working conditions of the cutting tools. The presence of CrB2 micropowder and VN nanopowder promoted densification of the matrix and adhesion between the diamond grits and the Fe‒Cu–Ni–Sn matrix.