Effects of normal loads on the friction and wear properties of metals and ceramic against cermet in vacuum

Friction and wear tests were carried out using five kinds of pins (Ag, Ti, Mo, Stainless steel 303, and WC) against a TiC-based cermet disk at four kinds of loads (2.5–10 N) under unlubricated conditions in a vacuum. A topographical analysis was also performed on the micro-asperities of the wear surfaces to estimate the behavior of the wear particles, the degree of surface damage and the wear rate. As a result, the following were found: (1) The wear rates of pins increased abruptly at the higher load than 5.0 N for WC pin, at 7.5 N for Mo pin, and at 10.0 N for Ti pin, respectively. The wear rates of austenitic stainless steel (SUS303) and Ag pins depend on the amount of the wear particles transferred to the mated disks preferably to the loads. (2) The greater the wear particles of pins transferred to the disk, the greater the wear rate of pin becomes. (3) The wear rates of pins and disks depend on the topographical parameters such as the mean depth of micro-grooves, the mean tip radius of asperities, and the depth of mean line as suggested in the analytical results. (4) The mean friction coefficient depends on the depth of mean line on a disk.