Friction and Wear Characteristics of Polyvinylether (PVE) as a Lubricant for Alternative Refrigerant

The tribological characteristics of a synthetic lubricating oil of polyvinylether (PVE) for a alternative refrigerant have been studied using three different friction testers with polyolesters (POE), polypropylene glycols (PPG), hydrogenated coal-tar oil and traction oil. In boundary lubrication regime, PVE gave higher friction coefficient and lower wear amount than POE and PPG. The high friction and low wear of PVE with high viscosity-pressure coefficient were attributed to a solidified film formed in a conjunction zone of high contact pressure. Although the solidified film had a high shear strength leading to a high coefficient of friction, it had a high ability to prevent the direct contact between rubbing surfaces compared with a boundary film consisting mainly of the adsorbed molecules of POE. The tribological characteristics in boundary lubrication are effected by two kinds of boundary films, adsorbed film and solidified film.