Effects of Temperature and Addition of Zinc Carboxylate to Grease on the Tribological Properties of PA66 in Contact with Carbon Steel

In this study, the influence of temperature on the tribological properties of unreinforced or glass-fiber reinforced PA66 in contact with carbon steel under boundary lubrication with grease was studied when considering the temperature dependence of the mechanical properties on the sliding surface of PA66 and the tribochemical reaction to zinc carboxylate additives in grease. XPS and ToF-SIMS analyses revealed the formation of a carboxylate tribofilm on the steel surface and a zinc sulfide reactive film on the PA66 surface, which are related to the tribochemical reaction of the additives present in the grease applied. The formation of the tribofilm contributed to an improvement of the tribological properties, particularly at 80 °C.