Wear Control in a Lubricated Contact Through Externally Applied Electric Current

Abstract

It has been reported earlier that when an electric current is externally applied between two sliding surfaces in a lubricated contact, an electrochemical cell is produced with the lubricant acting as an electrolyte and two sliding surfaces acting as electrodes. In this paper, the effect of an externally applied direct current on friction and wear of a sliding steel pair lubricated by engine oils has been investigated using a ball on disk machine. The current was passed through the contact by connecting the ball and disk specimens to a current source. It has been observed that the magnitude and the direction of current can significantly alter wear of sliding surfaces but does not greatly impact friction coefficients. The wear of the cathode surface decreased while that of the anode surface increased compared to the condition when no current passed through the contact. It was also observed that wear on anode and cathode surfaces was influenced by lubricant chemistry. The wear reduction on cathode surface is believed to be related to the modification of elemental composition of lubricant derived surface films due to the passage of an electric current.

KEY WORDS:

• Friction
• Wear
• Electric Current
• Engine Oils