Friction and Wear of Semicrystalline Polymers Sliding Against Steel Under Water Lubrication

Two types of experiments were carried out in this work. In one experiment, the smooth steel sphere was slid on polymer plates at a very low speed. Water reduced to some extent or very much the friction of polymers. In another experiment, the polymer pins were rubbed against the stainless steel disk at various speeds. In the sliding of polymers on the disk without the transferred polymer, a slight reduction of friction generally occurred under boundary lubrication; however, it occurred clearly in some cases on the disk with the transferred polymer. In these experiments, surface roughness plays an important role in boundary lubrication with water. The wear of polymers increases generally under lubrication. The amount of polymer transferred under lubrication is similar to that transferred in the dry condition. However, the features of worn surfaces of polymers under lubrication are different from those in a dry condition. The mechanism of polymer wear under lubrication is discussed on the basis of these findings.