Wear Characteristics of Mixed Lubricious Oxide Coatings

Recently, solid lubricant materials such as graphite, MoS2, WS2 etc. have been developed to meet the engineering requirements for lowering friction and wear of the components. However, they are limited in terms of their high temperature capabilities as well as their wear characteristics. In this paper we propose novel thermal spray lubricious oxide coatings based on a crystal chemical approach. The crystal-chemical approach is based on mixed oxides having difference in ionic potentials and can be used to predict the extent of adhesive interactions between two or more oxides at a sliding interface; hence, it can be used to predict frictional performance. Different combinations of the oxide materials are chosen based on their ionic potential differences and plasma sprayed to a thickness of 150 to 200 microns. Their composition, microstructure and room temperature and high temperature wear characteristics are reported in this paper.