The Friction and Wear Behavior in Controlled Alternative Refrigerant Atmosphere

Abstract

Increased wear occurred in the actual refrigeration compressor when HFC refrigerants were substituted for CFCs to comply with the Montreal Protocol. A cause of this increased wear was believed to be the inferior extreme-pressure (EP) or antiwear capability of the alternative refrigerant HFC-134a as the environment gas, compared to that for CFC-I2 refrigerant which is currently used. However, under some severe conditions, it was found that the alternative also showed some antiwear or EP effect by forming a fluoride layer on a sliding surface. The reason HFC-134a did not exhibit a lubricating effect, even though it had some capability to form a fluoride layer, was that the sliding condition required for HFCs to form a protective layer was more severe than that occurring in actual compressors. The mechanism of the atmospheric effect of refrigerant gases on friction and wear is also discussed.