Enhanced high temperature microwave absorption of La0.9Sr0.1MnO3/MgAl2O4 composite ceramics based on controllable electrical conductivity |
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| Affiliation: | 1. State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi′an 710072, China;2. School of Materials Engineering, Xi’an Aeronautical University, Xi′an 710077, China;1. Science and Technology on Thermostructural Composite Materials Laboratory, Northwestern Polytechnical University, 710072, Xi’an, China;2. NPU Institute of Culture and Heritage, Northwestern Polytechnical University, 710072, Xi’an, China;1. Science and Technology on Thermostructural Composite Materials Laboratory, Northwestern Polytechnical University, Xi''an, 710072, China;2. Xi''an Xinyao Ceramic Composite Material Co., Ltd., West Section of Biyuan 1st Road in High-tech Zone, Xi''an, China |
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| Abstract: | The high temperature microwave absorbing efficiency (HTMAE) of xLa0.9Sr0.1MnO3/(1 − x)MgAl2O4 composite ceramics was investigated by studying the crystal structure, electrical conductivity, and permittivity. The crystal structure of La0.9Sr0.1MnO3 and MgAl2O4 were maintained, but the Mn3+ and Al3+ ions were exchanged with each other through doping. The conductivity and permittivity of the composite ceramics increased with the increase of La0.9Sr0.1MnO3 content and test temperature. When x = 0.36, the electrical conductivity in La0.9Sr0.1MnO3 significantly enhanced the microwave polarization of the composite ceramics at high temperature. According to transmission/reflection modelling, the composite ceramics with x = 0.24 showed excellent HTMAE near the optimal thickness of 1.8 mm. Although the optimal thickness of the composite with x = 0.36 was reduced to 1.1 mm, the HTMAE was seriously lessened due to an impedance mismatch. xLa0.9Sr0.1MnO3/(1 − x)MgAl2O4 are promising as thin and efficient microwave absorbing materials at high temperatures and the microwave permittivity can be further enhanced by adjusting the conductivity of La0.9Sr0.1MnO3. |
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| Keywords: | LSM Microwave absorbing High temperature DC conductivity Composite ceramics |
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