摘要 |
A hydraulic system containing a piston-type pump having wear surfaces containing copper or a copper alloy, and, optionally, a vane-type pump having wear surfaces containing steel, uses an antiwear hydraulic fluid having an oil of lubricating viscosity and minor amounts of zinc dithiophosphate and a wear moderating agent. The wear moderating agent can be aliphatic polyol esters, boric acid derivatives of aliphatic polyol esters, aliphatic amines, aliphatic polyamines, aliphatic imidazolines, or mixtures of any combination thereof. The aliphatic groups of the wear moderating agent are substantially straight-chained, and the wear moderating agent contains at least ten carbon atoms. |