Tribological behavior of spark plasma sintered ultrafine-grained WC-cobalt cemented carbides in dry sliding

Ultrafine-grained tungsten carbide-cobalt (WC-Co) cemented carbides with different Co content were fabricated by spark plasma sintering. Then, tribological behavior of the ultrafine-grained WC-Co cemented carbides were studied by performing sliding wear tests with grinding balls made of GCr15 bearing steel (HRC 62 similar to 66) and Ti-6Al-4V titanium alloy (HRC 36). When the grinding ball is composed of GCr15 steel, the time required to reach the stable friction stage decreases with the increase in cobalt content, whereas the friction coefficient and wear rate tend to increase, and the wear type is abrasive wear. When the grinding ball is made of titanium alloy, the friction coefficient and adhesive wear volume first increase and then decrease with the increase in Co content, both reaching maximum values at 6 wt.% Co, and the wear type is adhesive wear.