不锈钢表面粗糙度对PTFE摩擦学性能的影响

Effect of Stainless Steel Surface Roughness on PTFE Tribological Properties

为了研究不锈钢表面粗糙度对聚四氟乙烯(PTFE)摩擦学性能的影响,使用不同目数的砂纸打磨以获得不同表面粗糙度的不锈钢表面,利用往复式点接触试验机评价PTFE球/不锈钢平面摩擦副的摩擦学性能。研究发现,干摩擦时,摩擦系数几乎不受表面粗糙度的影响,而PTFE的磨损率于不锈钢表面粗糙度达到200 nm时最小,主要是由于转移膜的存在且转移膜与粗糙表面之间的结合力较强。水润滑时,摩擦系数和磨损率均随着表面粗糙度的增加先减小后增加,即存在一个较优的表面粗糙度使得PTFE的摩擦学性能最佳,此时Ra为60 nm。这可以归结为光滑表面容纳水的能力有限而粗糙表面会造成严重的磨粒磨损。

To study the effect of stainless steel surface roughness on PTFE tribological properties under dry and water lubricated conditions,the sand papers with different sizes are used to sand the surfaces to different roughness.A reciprocating ball-on-plate tester is used to investigate the tribological properties of PTFE ball/stainless steel plate.The results show that the friction coefficient does not almost come under the influence of the surface roughness and the wear rate of PTFE decreases with the increase of the surface roughness under dry friction due to the strong bond strength between the transfer layer and the stainless steel surface.While under water lubrication,the friction coefficient and the wear rate firstly increase and then decrease with the increase of the surface roughness,when the surface is smooth,the friction interface is lack of sufficient lubricant because the space between the asperities couldn’t store abundant water,when the surface is rougher,the sharp asperities on the surface cause serious abrasive wear.It comes to the conclusion that when Ra is about 60 nm,the tribological properties is best.