Sliding friction wear of hydrogenated pure copper

The effect of cathodically charged hydrogen on the wear characteristics of pure copper has been investigated using pin on disc wear tests. Sliding distance and applied normal load were taken as wear test variables, while sliding velocity was kept constant. The tests revealed that cathodic hydrogen charging resulted in a reduction of the coefficient of sliding friction of copper. The coefficient of sliding friction was found to decrease with increasing charging time. Most of the wear debris of the hydrogen charged copper had a particle like shape and presented features of brittle fracture, whereas the wear debris of the uncharged copper was indicative of mechanical shearing and plastic deformation. The amount of copper wear debris was found to be a uniform function of charging time. A long time of charging produced more wear debris. The wear track of the hydrogen charged copper showed discontinuous smearing of copper and oxide particles, whereas the uncharged copper showed very smooth and uniform smearing of copper and oxide particles. Microcracks were observed in the wear tracks of the charged copper. Cathodic hydrogen charging was found to cause hardening in copper and the severity of hardening increased with increasing time.