Fundamental aspects of the electronic structure, materials properties and lubrication performance of sputtered MoS2 films

Abstract

Abstract An understanding of the fundamental properties of solid lubricants at the atomic level ( e.g. crystalline structure and chemical bonding to substrates) and their relationship to tribological performance is essential to the development of new lubricants to satisfy the demands of advanced mechanical technologies. Detailed measurements of the physical and chemical properties of the surfaces of lubricant films and their substrates, and of their bulk crystalline and electronic structures can be correlated with their friction, wear life and resistance to reactive degradation. In this paper experimental results concerning the electronic and crystal structures, film adhesion and bulk friction of sputter-deposited MoS 2 films are reviewed and discussed. A model using a molecular orbital description of the electronic energy levels of MoS 2 is presented that can be used to interpret these data. This model also provides a rationale for the differences in lubrication effectiveness between NbSe 2 and MoS 2 , and it provides predictive capabilities for improving the performance of MoS 2 films.