Increased wear occurred in the actual refrigeration compressor when HF
C refrigerants were substituted for CFCs to comply with the Montreal P
rotocol. A cause of this increased wear was believed to be the inferio
r extreme-pressure (EP) or antiwear capability of the alternative refr
igerant HFC-134a as the environment gas, compared to that for CFC-12 r
efrigerant which is currently used. However, under some severe conditi
ons, it was found that the alternative also showed some antiwear or EP
effect by forming a fluoride layer on a sliding surface. The reason H
FC-134a did not exhibit a lubricating effect, even though it had some
capability to form a fluoride layer, was that the sliding condition re
quired for HFCs to form a protective layer was more severe than that o
ccurring in actual compressors, The mechanism of the atmospheric effec
t of refrigerant gases on friction and wear is also discussed.