Lubrication Mechanism of Solid Lubricants in Oils

Abstract

Lubricating properties of machine oils containing such solid lubricants as (CF)n, MoS2, graphite, etc., were studied on a pin and disk machine by measuring an electric contact resistance and a friction force. After lubrication tests, solid lubricants films and transferred wear particles on worn surfaces have been observed by means of an XMA and an optical microscope. The wear mechanism of metals was analyzed considering a mean peak to peak distance and a mean depth of scratches on worn surfaces. The effects of particle size and concentration of (CF)n, and a suspending agent AD-6 on the friciton and wear process were also discussed. It was found that when the large number of (CF)n particles can penetrate into the interface in accordance with an oil flow, they show a good performance as a lubricant but solid lubricant films were not formed on worn surfaces besides graphite particles embedded on those of a copper disk.