Pseudoplastic deformation pits on polished ceramics due to cavitation erosion

In a previous study, pseudoplastic deformation pits created by cavitation exposure were reported in silicon nitride and zirconia. In this research, further comparison of the size and number of pits between several silicon nitride and zirconia materials is carried out. The pits are larger and much more numerous in silicon nitride than in zirconia although silicon nitride is harder than zirconia. An explanation of this phenomenon is given. Also, in the previous study it was reported that apparently a partially stabilized zirconia with yttria oxide developed a delay in the phase transformation from tetragonal to monoclinic after being exposed to cavitation. In this research, further experiments related with this phase transformation delay are carried out. Also, the phase transformation is verified with X-ray diffraction analysis. It is concluded that the “activation” of the partial stabilized zirconia happens regardless of the oxide used to stabilize it.