Improvement in Running-In Process by Applying External Voltage.

Abstract

The effect of an electric field applied between rubbing surfaces on friction and wear characteristics was examined using a ball-on-disc testing apparatus under mixed or boundary lubrication conditions. When the friction characteristics improved, the balls were abrasively worn by the mating discs on which oxide films were formed mainly by anode oxidation. On the other hand, in the cases where friction was not decreased, the main wear mechanism was adhesive, similar to the cases without an electric field. The lowest limits of the voltage and short-circuit current of the electric field were determined in order to improve the friction characteristics. In addition, high voltage and short-circuit current caused the friction characteristics to deteriorate due to breakdown of the oil film builtup. Therefore, application of electric field results in quick running-in, and it seems to be better to cease applying the electric field after the friction characteristics improve.