Tribological Performances of Polymer-Based Coating Materials Designed for Compressor Applications

Abstract

With increasing importance of advanced coating materials for use in interacting parts of air-conditioning compressors, several commercially available polymer-based coatings (PTFE/ Pyrrolidone-1, 2, PTFE/MoS2-1, 2, Fluorocarbon, PEEK/PTFE and PEEK/Ceramic coatings) were tribologically evaluated. Friction and wear behavior of these coatings, deposited on gray cast iron were in-situ measured using a specialized pin-on-disk tribometer. The experiments were performed under compressor specific conditions, namely under oscillatory motion simulating piston-type compressor and unidirectional motion simulating swash plate-type compressor operation. Also, the tribological properties of newly developed ATSP-based coatings deposited on aluminum substrates were evaluated under ball-on-disk, unidirectional sliding experiments. Polymer-based coatings exhibited excellent frictional properties, while their wear resistance was also acceptable, even though lower compared to hard coatings. However, the wear debris generated at the interface acted as a third-body solid lubricant with a beneficial role in their overall performance. ATSP coatings blended with fluoroadditives showed superior frictional behavior than pure ATSP coatings, and their wear rate was extremely low compared to commercially available PTFE-based coatings.