Corrosion Resistance and Tribological Characteristics of Polyaniline as Lubricating Additive in Grease

Polyaniline (PANI) was doped as lubricating additive to afford grease. The effect of PANI on the physicochemical characteristics, corrosion resistance, and tribological performances of lubricating grease was investigated in details, and the tribological action mechanisms of lubricating grease were analyzed in relation to worn surface analyses by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscope (EDS). Results indicate that the PANI-doped grease has superior conductive and thermal properties. And PANI-doped grease has an excellent corrosion resistance, which is attributed to the isolation effect and the compact passivated film generated by reaction of PANI and metal. In the meantime, the PANI-doped grease performs superior friction reduction and wear resistance under different applied loads and frequencies. It is mainly ascribed that the PANI can perform like spacers to avoid direct contact between the contact interfaces, and the protective tribofilm is generated by physical adsorption and chemical reaction.