Microstructure and Properties of Al₂O₃-ZrO₂ Ceramics Prepared by Microwave Sintering

Abstract:

ZrO₂ doped with 7.5% (volume percent) nanoalumina ceramics were prepared by microwave sintering processes. The effects of nanoalumina additions and various sintering temperature on densification, phase composition, microstructure and mechanical properties of Al₂O₃-ZrO₂ ceramics were investigated. The results show that the m-ZrO₂ phase transformed into t-ZrO₂ during the process of microwave sintering. Relative densities between 95% and 99% were attained in the different conditions. In any cases the grain size was maintained at a submicron scale at a processing microwave sintering. The presence of Al₂O₃ grains had an effect of hindering grain growth of ZrO₂ grains. When the microwave sintering temperature was 1500°C, 7.5Al₂O₃-ZrO₂ composite ceramics presented excellent mechanical properties: HV=12.0 GPa, σ_f=715.7 Mpa, K_IC=11.9 MPa·m^1/2. Compared with that of pure ZrO₂ ceramic, the bending strength and the fracture toughness were improved 45% and 23% at least, respectively. The fracture mode was associated with sintering temperature: when the sintering temperature was 1350°C~1450°C, the intergranular fracture and transgranular fracture coexisted; when the sintering temperature was 1500°C, intergranular fracture was the main fracture mode.

• Periodical: Key Engineering Materials (Volume 633)
• Pages: 193-197
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.633.193
• Online since: November 2014
• Authors: Yun Long Ai*, Xiang Hua Xie, Wen He, Bing Liang Liang, Wei Hua Chen
• Keywords: Al₂O₃, Fracture Toughness, Microstructure, Microwave Sintering, Zro₂

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