Hybrid silica-carbon bilayers anchoring on FeSiAl surface with bifunctions of enhanced anti-corrosion and microwave absorption

Abstract

Most of the magnetic microwave absorbers are ineffective in extreme corrosive environments of acids and alkalis which abruptly reduce their performance. Therefore, it is urgent and worthwhile to produce the bifunctional materials with excellent corrosion resistance and microwave absorption property. This work presents the in-situ growth of double shells of silica and carbon on FeSiAl (FSA) alloy surface to obtain an integrated FSA@SiO2@C hybrid structure via combined Stöber and catalytic chemical vapor deposition (CCVD) techniques. The hybrid structure acquires the strengthened bi-functional for anti-corrosion and microwave absorption due to the excellent corrosion shielding protection and well dielectric properties of SiO2 and carbon hybrid structure. Importantly, the hybrid morphology retains excellent stability of more than 150 h in 5.0 wt% NaCl acid solution. Moreover, FSA@SiO2@C hybrid possesses enhanced microwave absorption performance with a minimum reflection loss (RLmin) of −46.75 dB at 5.74 GHz with a matching thickness of 3.5 mm, and the effective bandwidth (RL < −10 dB) up to 7.73 GHz at 2.5 mm thickness. While considering the excellent corrosion resistance and microwave absorption characteristics, the novel hybrid organization opens up the opportunity to design materials for valuable addition at commercial level.