From our study, WC-3mass%TiC-2mass%TaC binder-less cemented carbide with dispersed sphere-shaped carbon has excellent performance maintaining hydrodynamic lubricant film under the high PV value condition at the mechanical seal ring application sealing the water. The tribological performances under dry condition were evaluated in this study. In the result, this alloy showed high tribological performances concerning to the frictional torque increasing, the temperature increasing, and the wear on frictional surface. It means that this alloy is a suitable material for solid lubrication associating the contacts between opposed two sliding surfaces directory.

*Dept. Mech. Cntl. Eng., Kyushu Institute of Technology