The effect of Al2O3 on the high‐temperature oxidation resistance of Si‐B‐C ceramic under air atmosphere |
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| Authors: | Qingliang Shan Jianbao Hu Yanmei Kan Dewei Ni Le Gao Xiaowu Chen Shaoming Dong |
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| Affiliation: | 1. State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, China;2. Structural Ceramics and Composites Engineering Research Center, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, China;3. ShanghaiTech University, Shanghai, China;4. University of Chinese Academy of Sciences, Beijing, China;5. Shanghai Institute of Materials Genome, Shanghai, China |
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| Abstract: | Si‐B‐C ceramics were prepared through reaction sintering, and the influence of Al2O3 addition on the high‐temperature (1100‐1300°C) oxidation behavior of the material under air atmosphere was studied. The erosion behavior and mechanism are determined from the measurement of weigh changes, microstructure observations, and characterization of the generated oxides on postexposure specimens. Results show that Al2O3 is enriched in the oxidized layer, inhibiting the volatilization of B2O3 and impeding the crystallization ability of oxide (cristobalite). Narrower erosion layer and less weigh change are observed with Al2O3. Low‐frequency Raman results reveals that with the increase in Al2O3, the bending vibrations of the BO4 units and B‐O‐B stretching of the metaborate ring relative intensity are enhanced. Furthermore, high‐frequency Raman results shows that the relative proportion of high‐dimensional vibration modes Q3 and Q4 which result in a higher viscosity of melt and a greater resistance of oxygen diffusion are positively correlated with Al2O3. |
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| Keywords: | ceramic matrix composites oxidation resistance viscosity |
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