A STUDY OF WEAR RESISTANCE OF Cdiamond–(WC–Co)–CrB2 COMPOSITE MATERIALS FORMED BY SPARK PLASMA SINTERING

Abstract

In this work, the dependence of the wear rate by weight WR, the wear rate by volume WV, and the specific wear rate WS on the concentration of chromium diboride was determined in samples of composite diamond-containing materials (DCMs) of the Cdiamond–(WC–Co)–CrB2 system formed by spark-plasma sintering. It is shown that the addition of chromium diboride micro-powder CrB2 in the amount of 4 % reduces the values of the wear rate by weight WR, the wear rate by volume WV, and the specific wear rate WS from 8.92·10-5 to 4.54 10-5 g/m, from 8.6980·10-12 to 3.5717 10-12 m3/s, and from 7.16·10-13 to 3.9686·10-13 m3/(N·m), respectively.
The decrease in the wear rate of 25Cdiamond–66.74WC–4.26Co–4CrB2 DCM compared to 25Cdiamond–70.5WC–4.5Co DCM is due to the formation of a fine-grained structure of the carbide matrix, improvement of mechanical properties (bending strength Rbm and compressive strength Rcm, fracture toughness KIc and adhesion strength between diamond grains and the carbide matrix).
With a further increase in the content of chromium diboride from 4 to 10 % in the composition of the 25Cdiamond–70.5WC–4.5Co composite, an increase in the values of WR from 4.54 10-5 to 6.44 10-5 g/m, WV from 3.5717 10-12 to 5.7087 10-12 m3/s and WS from 3.9686 10-13 to 5.3483 10-13 m3/(N·m) was found. The increase in the values of WR, WV, and WS in the 25 Cdiamond–61.1WC–3.9Co–10CrB2 sample compared to the 25 Cdiamond–66.74WC–4.26Co–4CrB2 sample is due to the deterioration of its mechanical properties.
The obtained results on the wear resistance of sintered samples of Cdiamond–(WC–Co)–CrB2 DCM allow their use for the manufacture of new tools for drilling hard rocks with increased mechanical and operational properties.