Sintering dense nanocrystalline 3YSZ ceramics without grain growth by plastic deformation as dominating mechanism

Abstract It is difficult to obtain nanocrystalline ceramic bulks due to its high surface activity at high temperatures. In the study, in order to achieve both high density and ultrafine morphology, the plastic deformation was induced by an ultrahigh pressure at a deliberately selected temperature, which was much lower than the threshold temperature for rapid grain growth. According to the ultra-high pressure route, nanocrystalline 3YSZ ceramics without grain growth were fully densified at 900 °C under 1.5 GPa. Both direct microstructural observations and calculation results proved that the plastic deformation including high temperature yield and sliding played a dominant role in densification during the sintering process.