Surface modification by cathode spots of a vacuum arc

Cathode spots of a vacuum arc have the smart property to selectively remove oxide on a metal surface. Analyses of a surface treated by a vacuum arc revealed that various interesting surface modifications occurred during the removal of the oxide. The authors have investigated these effects to open up new applications of the vacuum arc. The cathode spots can remove inclusions which often cause surface defects. They attack not only oxide but also carbide inclusions and eliminate them from the surface by evaporation. Dry cleaning to remove the organic compound can also be possible. Degreasing (removal of grease) proceeds in parallel to the removal of oxide. The vacuum arc treatment results in the increase of hardness in the surface layer due to the rapid heating and quenching.