Microwave Sintering of Zirconia Materials: Mechanical and Microstructural Properties

Commercially, 3 mol% Y₂O₃-stabilized tetragonal zirconia (70–90 nm) compacts were fabricated using a conventional and a nonconventional sintering technique; microwave heating in a resonant mono-mode cavity at 2.45 GHz, at temperatures in the 1100–1400°C range. A considerable difference in the densification behavior between conventional (CS) and microwave (MW) sintered materials was observed. The MW materials attain a full density of 99.9% of the theoretical density (t.d.) at 1400°C/10 min, whereas the CS reach only 98.0% t.d. at the same temperature and 1 h of dwelling time. Therefore, the MW materials exhibit superior Vickers hardness values (16.0 GPa) when compared with CS (13.4 GPa).