ramics are hard, brittle, and chemically inert under most environments. They wear by abrasion and fracture. Since brittle fracture is very sensitive to stress intensity factors, ceramic wear is dominated by stress intensity at various scales. Under mild wear regime, asperity stresses cause intergranular cracking leading to grain pull-out and substrate fatigue process from repeated cycles of stresses. Since ceramics are hard, the wear particles are relatively hard and large as contrasted with wear debris in the metal systems. This eventually introduces large third bodies in the contact. The presence of third bodies intensifies the stress intensity and more fractures take place. Wear transitions occur.