The controlled preparation and stability mechanism of partially stabilized zirconia by microwave intensification

Abstract Partially stabilized zirconia (PSZ) occupies an important application portion in ceramics materials and refractories materials. In this work, calcium oxide-partially stabilized zirconia (CaO-PSZ) ceramics were prepared from fused zirconia by microwave sintering, with its microstructure and stability properties characterized by XRD and SEM. Results indicated that the heating rate, cooling rate, quenching temperature and isothermal treatment time rendered different influence on the stability properties, which was mainly ascribed to the reversible martensitic transformation of zirconia ceramics. Additionally, a mixed-phase composed by cubic phase ZrO₂ (c-ZrO₂) and monoclinic phase ZrO₂ (m-ZrO₂) appeared after fused zirconia treated by microwave sintering at 1450 °C for 2 h, indicating the formation of CaO-PSZ ceramics, which the finding was consistent with the SEM and EDAX analysis. Meanwhile, CaO stabilizer precipitated behavior at the crystal boundary, with the formation of acicular grains and fine particles, further rendering a toughening effect to CaO-PSZ ceramics. This work can provide important theoretical and practical significance for applications of microwave sintering to prepare CaO-PSZ ceramics material, even extending further applications in functional materials and structural materials