Solid Film Deposition and Non-Sacrificial Boundary Lubrication

This paper reports the results of studying various approaches in non-sacrificial boundary lubrication in which the deposition of a beneficial surface layer is the result of a chemical reaction involving one or more components in the lubricating fluid but not the metal surface itself. This is in contrast to the conventional approach which involves the rubbing surfaces as reactants with the components in the lubricant and usually promotes wear as the result of chemical change of the surfaces. The most interesting findings show that a reaction between a molybdenum complex and a mixture of zinc dialkylphosphorodithioates produced in situ deposition of MoS2 and some other unidentified crystalline material. Effective reductions in friction and wear were obtained. Electron diffraction patterns of the worn metal surface established the presence of MoS2. Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Pittsburgh, Pennsylvania, October 16–18, 1962.