Solid Lubrication of Ceramic Sufraces by IAD (Ion-Assisted Deposition)-Silver Coatings for Heat Engine Applications.

摘要

In this study, an investigation was made of the tribological characteristics of alumina ceramics coated with silver by means of ion-assisted deposition (IAD). Tests were performed at temperatures up to 400(degree)C on an oscillating-slider wear test machine capable of simulating the reciprocating motion of a ring/cylinder system. The results showed that higher test temperatures caused greater wear damage and increased friction for uncoated alumina. At 400(degree)C, the wear rates of the alumina-alumina test pairs were 8 to 10 times higher than those tested at room temperature. The steady-state friction coefficients were also fairly high, typically ranging from 0.8 to 1.1. In contrast, the wear rate of IAD-silver coated flats was virtually zero and the wear rates of the counterface pins were reduced by a factor of 72. Friction was also reduced to about half to one third of those for the uncoated pairs. Surface and structure analytical investigations together with the hot-hardness testing of substrate alumina at temperatures up to 600(degree)C were performed to ascertain the mechanisms responsible for the friction and wear behavior of both alumina-alumina and alumina-IAD-silver coated alumina pairs. 28 refs., 8 figs.