Structural Instability and Microstructural Change of La3+-Doped M-Type Calcium Ferrite |
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| Authors: | Tsang-Tse Fang Jiung-Bin Hwang |
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| Affiliation: | Department of Materials Engineering, National Cheng Kung University, Tainan, 70101 Taiwan, Republic of China |
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| Abstract: | Several compositions were selected to investigate the formation of M phase. It was found that by reducing Fe2O3 or increasing La2O3, we were able to obtain pure M phase, as deduced from X-ray patterns, but CaO.2Fe2O3 was always observed in micrographs of the polished surfaces. The instability of the M phases might be due to the distortion of the lattice structure. The development of humps in the microstructures was related to the distribution of La3+. Retardation in the formation of M phase when sintered in O2 could be interpreted by the defect equation. |
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| Keywords: | calcium ferrites lanthanum microstructure instability |
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