1. Effect of Y0.5Er0.5Ho0.5Yb0.5O3 addition on the microstructure and thermal stability of continuous alumina fibers.
- Author
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Chen, Yutong, Liu, Wensheng, Ma, Yunzhu, Yao, Shuwei, and Wang, Juan
- Abstract
Continuous alumina fibers with excellent thermal stability are essential in high-temperature applications. In this study, 0~1 wt% Y
0.5 Er0.5 Ho0.5 Yb0.5 O3 were added to the alumina fibers to enhance thermal stability. The impact of Y0.5 Er0.5 Ho0.5 Yb0.5 O3 addition on alumina fibers' transformation and microstructure evolution of during the sintering process was systematically studied. The influence of single- and two-step sintering processes on the fiber microstructures was elucidated. The results suggested that adding Y0.5 Er0.5 Ho0.5 Yb0.5 O3 impeded fiber densification, inhibited alumina grain growth, and enhanced the thermal stability of fibers. Using a two-step sintering process facilitated the achievement of fully dense alumina fibers with fine grains. The alumina fibers added with 1.0 wt% Y0.5 Er0.5 Ho0.5 Yb0.5 O3 exhibited a remarkable strength retention rate of up to 93% after exposure to 1200 °C for 10 h. The TEM analysis revealed that rare earth elements segregation at α-Al2 O3 grain boundaries due to their larger radius than the Al element contributed to stabilizing the microstructures of α-Al2 O3 fibers at high service temperature. Highlights: The addition of Y0.5 Er0.5 Ho0.5 Yb0.5 O3 impeded fiber densification, inhibited alumina grain growth. After being held at 1200 °C for 10 h, the strength retention rate of alumina fiber with 1 wt% Y0.5 Er0.5 Ho0.5 Yb0.5 O3 is about 93%. Rare earth elements segregate at the grain boundary of alumina fiber, stabilizing the size of fine α-Al2 O3 grains. [ABSTRACT FROM AUTHOR]- Published
- 2024
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