Solubility of HFC134a in lubricants and its influence on tribological performance

The influence of dissolved refrigerant HFC134a on tribological performance of lubricants for HFC refrigerants was investigated by measuring the solubi lity of lubricants, and the viscosity reduction and change in oil film thic kness of HFC134a/lubricant mixtures in a reciprocating motion. The wear cha racteristics of an aluminum alloy for the mixtures ware also studied. It wa s found that HFC134a dissolution was exothermic reaction, and the solubilit y defined by the saturated concentration of HFC134a in lubricants decreased with an increase in the cohesive energy density of lubricants. The reducti on in viscosity was affected not only by HFC134a concentration in the lubri cants but also by the mean molecular weight of lubricants. Tile decrease in oil viscosity by dissolved HFC134a made the wear characteristics worse due to reducing the oil film thickness.