Damage initiation and evolution in silicon nitride under cyclic and rolling contact.

Out of various structural ceramics, silicon nitride is considered to be the first choice of material for the modern hybrid bearing applications due to their exceptional material properties. Nonetheless, the damage mechanisms in silicon nitride undergoing non-conforming contact are still a topic of research due to their scatter in strength and brittle nature. Therefore, this study improves the understanding of damage mechanisms in gas pressure sintered silicon nitride (GPSN) material which is considered to be more feasible and easier to manufacture. The uniqueness in this thesis arises from the combination of two different model experimental (cyclic and rolling) work with numerical simulations. Furthermore, for both experiments systematic parametric studies under various tribological scenarios were performed to elucidate minute details in terms of crack initiation and propagation. In addition, finite element (FE) simulations were employed to correlate the ongoing damage mechanisms.