The capability of hibonite elongated grains to influence physical, microstructural, and mechanical properties of zirconia toughened alumina-CeO2-MgO ceramics

This work investigated the capability of hibonite (CaAl12O19) phase on structure and microstructure of zirconia toughened alumina-CeO2-MgO ceramics. Three different additives (CeO2, MgO and CaCO3) were introduced into zirconia toughened alumina ceramics prepared by solid state reaction. X-ray diffraction and FESEM analyses were employed to observe the role of secondary phases especially hibonite and its influence on the microstructural features and other properties. Among the secondary phases present, EDX analysis revealed that hibonite phase contributed to elongated grains. Vickers indentations hinted a strong difference in the efficiency of compositional adjustment among the composites. The excellent Vickers hardness and fracture toughness results obtained for 3 wt.% CaCO3 additions showed the appearance of 5.9% hibonite with the value of 1485 HV and 7.10 MPa·√m, respectively.