Densification of copper oxide doped alumina toughened zirconia by conventional sintering

• Published in: Ceramics international Vol. 48; no. 5; pp. 6287 - 6293
• Main Authors: Abbas, M.K.G., Ramesh, S., Sara Lee, K.Y., Wong, Y.H., Tan, C.Y., Johnson Alengaram, U., Ganesan, P., Musharavati, Farayi, Zalnezhad, Erfan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2022
• Subjects: Alumina-toughened zirconia; ATZ; Conventional sintering; Copper oxide; Sintering additive; Sintering additive; Conventional sintering; Copper oxide; Alumina-toughened zirconia; ATZ
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2021.11.171

The effect of copper oxide doping (0.05–1 wt%) on the densification, microstructure evolution and mechanical characteristics of alumina toughened zirconia (ATZ: 80 wt% Y-TZP + 20 wt% Al2O3) ceramic composites was investigated. Green samples were pressureless sintered using a short hold time of 12 min at temperatures varying from 1250 °C to 1500 °C. The incorporation of up to 0.2 wt% copper oxide was beneficial in promoting densification at low sintering temperature and improving the mechanical properties of ATZ without affecting the tetragonal phase stability. It was found that 0.2 wt% copper oxide addition was most efficacious, and the samples could attain a relative density of approximately 92% at 1250 °C, approximately 97% dense at 1350 °C and above 99% dense at 1450–1500 °C. This approach was also accompanied by an improvement in the Vickers hardness (12.7 GPa) and fracture toughness (6.94 MPam1/2) when consolidated at 1450 °C/12 min. In comparison, the undoped composite exhibited relative densities of approximately 80% at 1250 °C, 87% at 1350 °C and approximately 97%–98% at 1450 °C-1500 °C. However, the study also found that higher dopant levels (0.5 wt% and 1 wt%) was not beneficial because the tetragonal zirconia phase was disrupted upon cooling from sintering, resulting in the monoclinic phase formation. In addition, low densification and poor mechanical properties were obtained.