Effect of Shape of Sand Grains on Wear of Nitrile Butadiene Rubber in Crude Oil with Sand and their Mechanical Behavior

Friction and wear behavior of nitrile butadiene rubber in crude oil with sand was investigated by the reciprocating wear tester, while the movement of sand grains of different shapes during the wear process was also studied. Morphology and chemical composition of the worn surface of rubber were characterized by stereo microscope and field emission scanning electron microscope. The results show that the frictional coefficient and wear loss of the rubber in crude oil increased with the addition of sand. The main movement model of round-shaped sand grains was rolling within the desired range of load, and the grinding abrasive wear was generated on the rubber surface. The movement model of sharp sand grains changed from rolling to sliding when the applied load was above 95 N, and correspondingly the wear mechanism of rubber transformed into cutting abrasive wear. The above observed variation of movement model of different shaped sand grains by varying applied load and its effect on the wear mechanism of rubber was further confirmed by the research result on the mechanical behavior related with translational acceleration and rotational acceleration of sand grains. © All right reserved.