The invention is applied to a compressor assembly wherein a coating is applied to the pocket in the piston for sliding engagement with a shoe for reciprocating the piston. The coating is a composite of solid particles of a lubricant, suspended in an adhesive, bonded to the to the aluminum alloy defining the pocket. More specifically, the coating comprises particles of polytetrafluoroethylene (PTFE) suspended in an epoxy resin having a low cross-linking characteristic. The particles of PTFE are sub-micron in size and the ratio of PTFE to epoxy resin is optimally one to one. The thickness of the coating is between two and ten microns and preferably substantially four microns.