Effets de l’humidité sur le comportement des céramiques Al₂O₃, Si₃N₄ et PSZ en frottement à grande vitesse sur acier

Service Usure, Dpt Matériaux, CETIM

Abstract

In order to study the effects of humidity on the tribological behaviour of the sliding couple ceramics/steel, wear tests were carried out on a pin-on-disk tribometer ceramic pin on steel disk, pressure : 0.25 MPa, speed : 2.5 to 50 m/s) with a variation of humidity from 50 % to 100%.

This variation of humidity, which had made lightly heavier the wear of some alumina ceramics when the speed was over 30 m/s, resulted in a large increase of the wear of Si₃N₄ at the speeds lower than 10 m/s. But in the case of PSZ, little effect of humidity was detected, even at 15 m/s where the wear rate was quite high due to the phase transformation.

The wear mechanisms of ceramics seemed very complicated with the change of humidity, since the temperature could be considerable at the interface of friction. The wear was influenced not only by the modification of ceramics properties, but also by that of metallic counter face.