Micropitting occurs in gears and rolling-element bearings that operate in the mixed or micro EHL lubrication
regime. It manifests in many different ways depending on the loads, speeds, rolling and sliding velocities,
macrogeometry, surface topography, edge effects, metallurgy, and lubricant properties. The failure analyst
must discern whether the micropitting is a primary failure mode or a secondary failure that occurs because of
prior damage. Understanding the morphology of microitting is the key to determining the primary failure
mode and root cause of failure.
Several examples of micropitting in gears and rolling-element bearings are presented to ilustrate the
morphological variation that can occur in practice.