Effect of Y₂O₃-addition on the crystallographic and mechanical properties of the Ce-TZP/Al₂O₃ composite

Abstract

The effect of adding different Y₂O₃ contents on the physical and mechanical properties of Ce-TZP/Al₂O₃ composites was investigated. Ce-TZP/Al₂O₃ powder blends containing 1~10 wt% Y₂O₃ were compacted at 100 MPa-30 s and sintered at 1500 °C-2 h or 1600 °C-2 h. The materials were characterized by X-ray diffraction and scanning electron microscopy, Raman spectroscopy, relative density, and the mechanical properties of Vickers hardness and fracture toughness. After sintering, the relative density of the sintered samples varied between 92.7% and 96.3%. Furthermore, the addition of Y₂O₃ resulted in an increase in the amount of cubic zirconia (c-ZrO₂) and an increase in grain size in relation to the sample without the addition of Y₂O₃. With the increase of Y₂O₃ in the composition and consequent increase in the cubic ZrO₂ phase content, although the hardness values did not present statistically significant variations, indicating average value of 12 GPa, a decrease in fracture toughness values was observed (10.0~5.5 MPa.m^1/2) as a direct function of the reduction in the population of tetragonal zirconia grains, responsible for the toughening mechanism by phase transformation in these composites.

Keywords:
Ce-TZP/Al₂O₃; Y₂O₃ composite; Rietveld refinement; Raman spectroscopy; mechanical properties