Hardness and toughness enhancement of CeO2 addition to ZTA ceramics through HIPping technique

The aim of this research is to investigate the combined effects of CeO2 additions and hot-isostatic pressing sintering (HIPping) technique on the hardness and toughness of ZTA ceramics. Addition of CeO2 to ZTA ceramics leads to formation of a secondary phase (CeAl11O18) which played a vital role in affecting the Vickers hardness and toughness. Microstructure investigations showed that HIPping had a significant role in the removal of pores, and consequently affected both hardness and toughness of the samples. The highest Vickers hardness (1838.3 HV) and toughness (8.92 MPa·√m) were obtained with the 5 wt.% CeO2 additions that also had the highest bulk density (4.48 g/cm3) and the lowest percentage of porosity (0.37%).