Surface Relief Associated with Isothermal Martensite in Zirconia–3‐mol%‐Yttria Ceramics Observed by Atomic Force Microscopy

Surface relief associated with martensitic transformation—tetragonal‐to‐monoclinic phase transformation—that occurred during isothermal aging at temperatures of 400 and 473 K was observed via atomic force microscopy, using prepolished and thermally etched surfaces of zirconia–3 mol% yttria that was sintered at a temperature of 1923 K for 5 h. The isothermal martensitic transformation occurred first at grain boundaries and advanced into grain interiors as the aging time increased and then spread successively into the surrounding grains. The transformation area, which had an approximately round shape, increased as the aging time increased. The fine structure of the surface relief was composed of many tent shapes that were several nanometers high with an angle of ∼165°.