Influence of Si₃N₄ content on the physical and mechanical properties of zirconia-toughened alumina (ZTA) ceramic composites

Abstract

The zirconia toughened alumina (ZTA) samples with different Si3N4 additions which were uniaxial pressed and sintered at 160 °C for 3 h in no pressure, were studied. The Si3N4 addition was varied from 0 wt% to 2.5 wt%. XRD and scanning electron microscopy showed that the Si3N4 addition affected the phase composition and microstructure. The fracture toughness and hardness of the composite are characterized by the Vickers indentation method. The results show that the mechanical properties are associated with the addition of Si3N4. The maximum value of Vickers hardness (1454 HV) and fracture toughness (8.06 MPa.√m) was measured from the sample with 1 wt% Si3N4 additions. However, the Al6Si2O13 phase was obtained when the contents of additional Si3N4 excess 1 wt%. This will cause significantly decreasing of the mechanical properties of the ZTA-Si3N4 composite.