Evidence of Bilevel Solubility in the Bimodal Microstructure of TiO2-Doped Alumina |
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| Authors: | Miaofang Chi Hui Gu Xin Wang Peiling Wang |
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| Affiliation: | State Key Laboratory of High-Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 20050, China |
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| Abstract: | A phenomenon of bilevel solubility was observed in a TiO2-doped (2.0 wt%) alumina with bimodal microstructure sintered in N2. Surface contributions to dopant signals in individual grains were identified and removed, using a spatially resolved energy dispersive spectroscopy analysis. Two levels of solubility, 1.005 ± 0.166 and 0.504 ± 0.082 mol% of TiO2 in Al2O3, were obtained for anisotropic and equiaxed grains, respectively. No grain size dependence of solubility was found, but segregation of SiO2 to boundaries with the anisotropic grains was observed. This phenomenon was explained by the incorporation of Ti3+ into the Al2O3 lattice during the abnormal grain growth caused by SiO2 liquid under a reducing atmosphere. |
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| Keywords: | alumina solubility microstructure |
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