High efficiency microwave absorption properties of α−SiCp/α−SiCnw/SiO2/C composites with multi−interface hybrid SiC nanowires prepared by heterogeneous nucleation−growth mechanism

There are few reports about the electromagnetic wave (EMW) absorption properties of α−SiC based composites, and almost all of them focus on β−SiC polymorphs. In this study, α−SiC p /α−SiC nw /SiO 2 /C hybrid composites (sample SiC−C1500) with heterostructure α−SiC nanowires (α−SiC nw ) of multiple interfaces 4H−SiC/6H−SiC/SiO 2 /C were successfully prepared using mixed powder (α−SiC+m−SiO 2 +C) as raw material based on the heterogeneous nucleation−growth mechanism, and their microwave absorption properties were investigated. Meanwhile, the samples SiC−V2150 and Si−C1500 were obtained by vacuum calcination (α−SiC+m−SiO 2 +C) at 2150 0 C and carbothermal reduction (Si+m−SiO 2 +C) at 1500 0 C, respectively, and their phase compositions were α−SiC p /C and β−SiC p /β−SiC nw /SiO 2 /C, respectively. The sample SiC−C1500 exhibited excellent EMW absorption properties, with a minimum reflection loss (RL min ) value of −18.37 dB at a thickness of 1.3 mm, and a maximum effective absorption bandwidth (EAB max ) value of 4.9 GHz at a thickness of 1.5 mm. In contrast, the EMW absorption performance of the samples SiC−V2150 and Si−C1500 was obviously poor, which was consistent with the RCS (Radar Cross−Section) simulation results. The formation of α−SiC p /α−SiC nw /SiO 2 /C composites (sample SiC−C1500) containing 4H−SiC/6H−SiC/SiO 2 /C multi-interfaces heterostructure α−SiC nanowires (α−SiC nw ) was analyzed. The excellent EMW absorption performance of SiC−C1500 sample could be attributed to the effective regulation of α polymorphs, nanowire heterostructure, multi−component hybridization. This study supplies a helpful experience and reference for improving the high temperature EMW absorption performance of SiC matrix composites.