Wear in boundary lubrication

Abstract

Wear is a complex subject. Wear studies under lubricated conditions can be classified into two categories: wear mechanisms study of the materials under ‘lubricated’ conditions, and the evaluation of the lubricant chemistry using the same materials. Much confusion exists in the literature because these two communities historically do not interact frequently to understand each other's views. In the 1980s, material science research was emphasized around the world. As a result, wear studies began to flourish, examining various new materials for potential applications in new technologies. Since new materials came in many different forms, a wide variety of wear test geometries and test methods were developed for solids, coatings and thin films. Many of the wear test methodologies were established under a ‘dry’ condition (without the use of liquid lubricants). In this paper, the dry condition will be used as a baseline to compare various wear phenomena under lubricated conditions. Within this context, wear test procedures, basic assumptions and associated data interpretations will be examined. Wear mechanisms under lubricated conditions will also be discussed. Finally the current state of modelling under lubricated wear conditions will be reviewed.