The in-situ Observations of Friction and Wear Phenomena Under an Electric Current in Sliding Contact

Abstract

If friction aspects have an electric current, they have not only the friction and wear but also the wear of the influence of it. Pantographs of trains and so on do slide under it, so the wear progresses are influenced by the electric phenomena strongly. We think these wear act with each other and make far larger wear than single wear. But we haven't made the details of it clear yet. Firstly, we set the brief condition of our apparatus for experiments, and observe the phenomena in these conditions. For it, we use the way of observation, the in-situ observation way, and four friction materials of metals and carbon.
So far the wear is classified into some wear types. The adhesive wear shows the nearest wear ratio to the real wear of Pantographs. But the real one is larger than the range of the adhesive wear. And there have to be some causes to show this. We can think that an electric current influences the difference in the wear ratio. Then it is necessary how electricity have influences to them: to find phenomena that occur in wear processes and influence the increase of wear. They are the electric discharge and the fusion of materials.
It became obvious the electric discharge and the fusion of metals are two main things under the influence of the electricity. So far as the source of the heat for fusion, the constriction resistance is the biggest one and the heat of friction is far smaller than that of constrictions. It is the phenomena caused by the pass of electricity between two contact members. On the other hand, the electric discharge occurs at the space made between two members, a pin and a block, and it has the electric flow in the air. And this phenomenon makes more unevenness on the surface that causes more electric discharges and fusions.
After all the wear from electricity has greater influence than that of adhesion. In future we need to investigate the difference of the total wear volume between the electric discharge and the fusion.