Enhancement on high-temperature microwave absorption properties of TiB2–MgO composites with multi-interfacial effects

• Published in: Ceramics international Vol. 47; no. 4; pp. 4475 - 4485
• Main Authors: Liu, Xiongzhang, Luo, Hui, Yang, Jiaji, Wang, Xian, Qu, Zewen, Luo, Heng, Gong, Rongzhou
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.02.2021
• Subjects: High-temperature dielectric properties; High-temperature microwave wave absorption properties; Interfacial polarization; Magnesia; Titanium boride; Interfacial polarization; Titanium boride; High-temperature microwave wave absorption properties; High-temperature dielectric properties; Magnesia
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2020.10.008

TiB2–MgO microwave absorbing materials with TiB2 as the absorber, MgO as the matrix are prepared by spark plasma sintering (SPS). The influences of commercial TiB2 content and sintering temperature on dielectric and microwave absorption (MA) properties are studied. Besides, to optimize the MA performance, TiB2–MgO composite containing TiB2 synthesized by the carbonthermal process is prepared. Meanwhile, its high-temperature dielectric and MA properties are investigated. Indeed, both the commercial TiB2 content and sintering temperature play key roles in dielectric and MA properties, as they reaching 8 wt% and 1400 °C, the composite presents the optimal MA performance. For composite with synthetic TiB2 as the absorber, the temperature has a positive effect on dielectric and MA properties. The enhanced high-temperature MA properties with minimum reflection loss (RLmin) of −52.11 dB at 1.6 mm under 500 °C and effective absorption bandwidth (EAB, RL < −5 dB) of 4.2 GHz at 1.4–1.6 mm under 800 °C are obtained, which is mainly attributed to the temperature-dependent interfacial polarization compared to the temperature-insensitive conductivity. The excellent mechanical properties (flexural strength = 212.48 MPa), thin absorbing layer (d < 2 mm), enhanced thermal stability and high-temperature MA properties indicate that the TiB2–MgO composites can be considered as new candidates for high-temperature structure microwave absorbing materials.