Polishing wear. Photo courtesy GEARTECH © 2014.

Definition: Polishing is a from of wear caused by fine scale abrasion combined with the presence of chemically reactive antiscuff additives.

Identification: Mirrorlike surface finish. Smooth or wavy surface. SEM shows fine scratches oriented in the direction of sliding.

Discussion: Polishing can be very detrimental to the accuracy of gear teeth or bearing components. It is very common in differential side gears because their lubricants have aggressive antiscuff additves and rear axles are often contaminated with sand.

Prevention: Use less chemically active lubricant. Remove abrasives.

More Information: For more information on polishing, please submit a question to our “Ask an Expert” link. For assistance with a gearbox failure analysis, please visit our “Consulting” page.