Abstract:In order to find the appropriate counter materials of friction pairs for water hydraulic pump/motor,the friction pairs composed of 316 L stainless steel and four kinds of polyetheretherketone(PEEK),including pure PEEK,30% glassfiberreinforced PEEK(PEEKGF30),30% carbonfiberreinforced PEEK(PEEKCA30),and PTFE,graphite and carbonfiberreinforced PEEK(PEEKHPV) were taken as study objects,the friction coefficient and temperature of the contact surface of the friction pairs,and their wear extent under water lubrication were measured by using a MMW1 vertical universal friction and wear tester.The worn surface morphologies of the samples were analyzed by a laser scanning confocal microscope.The results show that,among the four sets of friction pairs,the friction pairs of 316 LPEEKHPV has the lowest friction coefficient,friction temperature and wear extent,they are more suitable for the counter materials of key friction pairs in water hydraulic pump/motor.The friction mechanism is abrasion and scratch for the counter materials of 316 L stainless steel and PEEKGF30,which results in the serious wear.The friction mechanism is scratch for the counter materials of 316 L stainless steel and PEEKCA30,while the friction mechanism is mainly scuffing for the counter materials of 316 L stainless steel and PEEKHPV,and the wear of the friction pairs is slight