Abstract

Inorganic lubricant additives such as zinc dialkyldithiophosphates (ZDDPs) and molybdenum dithiocarbamates are used ubiquitously in automotive engines. They decompose under tribological and thermal stress to coat engine components with anti wear films based on either polyphosphate glass or layered structures such as molybdenum disulfide that protect the components and thus increase their working lifetime. However, little is known about their mechanism of deposition and only by understanding this can we attempt to produce new anti wear materials. In this talk, we will explore the fundamental aspects of deposition of molybdenum disulfide onto steel substrates Using molybdenum disulfide films deposited by aerosol-assisted chemical vapour deposition (AACVD) as a model. We then show how this can be translated to chemical bath deposition to coat various relevant substrates such as steel, aluminium and diamond like carbon (DLC). We also explore the failure of molybdenum disulfide directly by the use of a novel electron microscopy-Tribology technique. Finally, we look to the future, developing a materials sorting map methodology to identify new anti wear materials. The case of chromium-doped molybdenum disulfide is explored.