Effect of Surface Roughness of Metalic Counterpart on Tribological Characteristics of NBR O-ring

Tribological tests for nitrile butadiene rubber (NBR) O-Ring against 316L stainless steel with different surface roughness were carried out on UMT-3 multi-function friction and wear tester. The effect of surface roughness of metallic counterpart on tribological behaviors of NBR was researched systematically. The variation of friction coefficient and wear volume were discussed, and the damage mechanism of rubber was revealed for different surface roughness. The results show that effect of the surface roughness on the friction and wear properties of nitrile butadiene rubber O-ring was remarkable. With the increase of the surface roughness, the friction coefficient in the stable stage decreased firstly and then increased. When the surface roughness was about 0.1 μm, the friction coefficient and wear rates of nitrile butadiene rubber were minimal and the worn surface presented a typical decorative wear pattern. When the surface roughness in the test block was too high or too low, the friction coefficient and the wear rates of the nitrile butadiene rubber were relatively higher and the wear mechanisms were adhesive wear and fatigue wear mainly.