The Influence of Manganese Oxide on the Sintering Behavior of Yttria Tetragonal Zirconia

The sintering behavior of yttria-stabilized zirconia, with the influence of small additions of MnO2(up to 1 wt %) sintered over the temperature range from 1250 deg. C to 1500 deg. C was investigated. It was found that the mechanical properties of Y-TZP were dependent on the dopant amount and sintering temperature. The results revealed that relative densities above 97.5% of theoretical (i.e. >5.95 Mgm-3) could be obtained in Y-TZPs sintered at low temperatures, 1250 deg. C and 1300 deg. C, with the additions of ≤0.3 wt% MnO2. In comparison to the undoped samples, the additions of up to 1 wt%MnO2 and for sintering up to 1350 deg. C was found to be beneficial in enhancing the Vickers hardness of the ceramic. The fracture toughness of Y-TZP however, was found to increase only in the 1 wt% MnO2-doped samples when sintered above 1400 deg. C. The relation between the measured mechanical properties is discussed with the emphasis on the role of the manganese oxide.