Enhanced high temperature microwave absorption of La0.9Sr0.1MnO3/MgAl2O4 composite ceramics based on controllable electrical conductivity. Issue 5 (May 2020)

• Record Type: Journal Article
• Authors: Jia, Hongyao; Zhou, Wancheng; Nan, Hanyi; Wang, Chunhai; Qing, Yuchang; Luo, Fa; Zhu, Dongmei
• Is Part Of: Journal of the European Ceramic Society. Volume 40:Issue 5(2020)
• Page Start: 1931
• Page End: 1937
• Publication Date: 2020-05
• Subjects: LSM -- Microwave absorbing -- High temperature -- DC conductivity -- Composite ceramics; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2020.01.010
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: The high temperature microwave absorbing efficiency (HTMAE) of xLa0.9 Sr0.1 MnO3 /(1 − x)MgAl2 O4 composite ceramics was investigated by studying the crystal structure, electrical conductivity, and permittivity. The crystal structure of La0.9 Sr0.1 MnO3 and MgAl2 O4 were maintained, but the Mn 3+ and Al 3+ ions were exchanged with each other through doping. The conductivity and permittivity of the composite ceramics increased with the increase of La0.9 Sr0.1 MnO3 content and test temperature. When x = 0.36, the electrical conductivity in La0.9 Sr0.1 MnO3 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. xLa0.9 Sr0.1 MnO3 /(1 − x)MgAl2 O4 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 La0.9 Sr0.1 MnO3 .