油润滑条件下Pb和Sn及Pb-Sn-Cu软金属刷镀层的摩擦磨损特性之研究

The Behavior of Friction and Wear of Pb-Sn System Brush Plating Layers under Oil Lubrication

采用电刷镀方法制取了含Cu量分别为1.7、5.7和11.5％(wt,下同)的3种Pb-Sn-Cu三元镀层,以及Sn、Pb两种单金属镀层,并在MM-200型摩擦磨损试验机上于20号机油滴油润滑下就这些软金属镀层的摩擦磨损性能作了对比试验,且对含Cu量为1.7％的Pb-Sn-Cu镀层的摩擦学特性随其厚度的变化作了进一步的研究。结果表明,在载荷为20MPa和滑动速度为0.6m/s的条件下,含Cu量为1.7％之三元镀层的摩擦磨损性能最好,而以含Cu量为11.5％之三元镀层的最差;在载荷为12.5MPa和滑动速度为0.6m/s的条件下,只有当厚度较大(>10μm)时,软金属镀层才具有低的摩擦系数和较长的磨损寿命。在Pb-Sn合金中添加适量(如1.7～5.7％)的Cu,可以提高镀层的耐磨性、承载能力和润滑性,但Cu含量太高(如11.5％)却会使镀层的润滑性和耐磨性变差。

Three Pb-Sn-Cu three-element plating layers with different Cu content and two single Pb and Sn plating layers had been obtained by brush plating technique. The measurements of wear resistance had been conducted on MM-200 testing machine with the drop-feed lubrication of 20# engine oil. The tests involved the comparison of wear resistance for the thick layers of different composition and the study of effect of plating layer thickness on their behavior of friction and wear, and further studied the characteristic on tribological property of Pb-Sn-Cu coating (Cu content is 1.7%) changed with their thickness. The results shown that the friction-wear property of three-element coating containing 1.7% of Cu is the best, whereas the characteristic of coating containing 11.5% of Cu is the worst. Under the given test conditions (carrying load is 12.5MPa and sliding speed is 0.6m/s), only if when the thickness is more than 10μm the soft metal coating is of lower friction coefficient and longer wear life. When the correct Cu (1.7 to 5.7 percent) is added into Pb-Sn alloy, the wear resistance, load carrying capacity and lubrication can be improved, but the lubricity and anti-wear property of coating can decrease as the Cu content is too high (such as 11.5%).