High antioxidant lamellar structure Cr2AlC: Dielectric and microwave absorption properties in X band

• DOI: 10.1016/j.jallcom.2020.157896
• Publication Date: 2020-11-20T13:14:14Z
• Authors: Yin Zhang; Jing Wen; Li Zhang; Haipeng Lu; Yang Guo; Xiaodong Ma; Min Zhang; Juhang Yin; Linglu Dai; Xian Jian; Liangjun Yin; Jianliang Xie; Difei Liang; Longjiang Deng
• Keywords: Reflection loss; Thermogravimetric analysis; Thermal Stability; Dielectric loss; Ku band; X band

Abstract Generally speaking, thermal stability is the key factor for microwave absorbers (MAs) at high temperature. In this paper, we first propose to apply a novel material called Cr2AlC (CAC) in the high temperature field. The self-made high purity CAC powder prepared by salt bath exhibits good microwave absorption performance and outstanding. Thermogravimetric (TG) analysis indicates the CAC begins to oxidize significantly above 800 °C. Moreover, the effective medium theory is adopted to calculate the microwave absorption performance for the CAC/paraffin composite material. We found that the sample with 70 wt% CAC (CAC70) has a minimum reflection loss of −25.09 dB at 11.08 GHz and its effective absorption bandwidth (below −10 dB) is 2.2 GHz (10.2–12.4 GHz) at the thickness of 2.00 mm, which indicates a thin layer of Al2O3 at room temperature will not affect the entry of electromagnetic waves and internal electrical losses. The high anti-oxidation layered structure CAC provides an opportunity to expand microwave absorption in high temperature applications.