Abstract:Tribological behaviors of nitrile rubber(NBR) in two kinds of medium,KCl solution with sand and distilled water with sand were investigated by the selfdesigned reciprocating wear tester,and the morphology and element content of NBR worn surface were analyzed by the field emission scanning electron microscope.The results show that,with the increasing of load,the friction coefficient of NBR is decreased and the wear loss is increased in two kinds of medium,but the variation degree of the friction coefficient and wear loss in the medium of KCl solution containing sand is higher than in the medium of distilled water containing sand.The wear mechanism of NBR in KCl solution with sand is corrosive wear and abrasive sliding erosion,and the wear mechanism in distilled water with sand is wet abrasive wear.The molecular chains of surface and subsurface of NBR are more prone to be ruptured under the action of K+,which leads to the generation of low molecular monomers with low molecular weight and dispersion,as well as the new branch network structure.