The effects of CeO2 addition on the physical, microstructural and mechanical properties of yttria stabilized zirconia toughened alumina (ZTA)

The effects of CeO2 addition on the structure, microstructure and fracture toughness of yttria stabilized zirconia toughened alumina (ZTA) ceramics were investigated. The CeO2 addition to the powder mixtures was varied from 0 wt.% to 15 wt.%. The powders of each composition were pressed into pellets and sintered at 1600 °C for 4 h under pressureless conditions. The fracture toughness of the sintered samples was determined by the Vickers indentation technique with a 30 kgf load. Based on the XRD analysis, only corundum and yttria doped zirconia phases were present. Shift in position of the zirconia peaks were observed due to the CeO2 addition. Microstructure investigations showed that the grain sizes of both corundum and yttria doped zirconia increased with increasing CeO2 addition. Fracture toughness and hardness values were dependent on the CeO2 addition. The highest fracture toughness (8.38 MPa.√m) and hardness (1688 HV) was obtained with the sample with 5 wt.% CeO2 additions. ZTA prepared with CeO2 additives showed an increase of 30% in fracture toughness compared to ZTA without additives.

► The ZTA composites showed increased in fracture toughness and hardness with increasing wt.% addition of CeO2.
► Sample with 5 wt.% CeO2 addition produced the highest toughness (8.38 MPa.√m) and hardness (1688 HV).
► CeO2 is useful for improving fracture toughness without deteriorating the properties of the ZTA.
► The presence of the Ce2Zr3O10 phase proved the over-solubility limit of CeO2 addition in ZTA composites.