Abrasion can result in very rapid wear. Here, a harder body can cut or spall a softer counterface. Abrasion is classified into two primary mechanisms. In two-body abrasion, a hard, rough surface scratches, cuts or spalls a softer surface. In three-body abrasion, a hard third body damages one or both of the sliding surfaces. This is usually due to grit or dirt getting in between the sliding interface.

two-body abrasion

three-body abrasion

Hard and well-adhered coatings and diffusion layers effectively reduce this wear. For effective reduction, the protected surface must be at least 20% harder than the abrasive.