Micropitting on a misaligned gear. Photo courtesy GEARTECH © 2013.

Definition: Micropitting is a localized surface damage phenomenon that occurs under mixed film lubrication conditions.

Identification: Micropitting results in a frosted or matte surface finish.

Discussion: Micropitting is very common in wind turbine gearboxes, and degrades gear tooth and bearing geometry, resulting in increased Hertzian contact stress. Micropitting may be self arresting, or it may develop into macropitting and lead to failure.

Prevention: Increase lubrication film specific thickness. Use an oil with high micropitting resistance.

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