Green chemistry approach enables ultra-broad microwave absorption and high corrosion resistance in traditional FeSiCr electromagnetic wave absorbers

Facing increasingly severe electromagnetic pollution and equipment corrosion issues, the development of absorptive materials that combine highly efficient broadband microwave absorption with good environmental stability is of growing importance. Traditional FeSiCr alloys, despite their favorable magnetic loss characteristics, suffer from inherent drawbacks, including impedance mismatch, a narrow effective absorption bandwidth ( EAB ), and susceptibility to corrosion, which significantly limit their practical applications. In this study, a new carbonitriding process based on a green chemical method was adopted. Melamine (C 3 H 6 N 6 ) was used as a carbon and nitrogen source, and carbonitriding FeSiCr was prepared by the solid solution of C and N on the basis of traditional alloying FeSiCr. The incorporation of C and N effectively optimizes the dielectric properties of FeSiCr, improves impedance matching, and introduces multiple loss mechanisms, thereby enhancing the electromagnetic wave absorption (EMA) performance, particularly in terms of bandwidth. As a result, carbonitrided FeSiCr exhibits pronounced reflection loss and absorption capability. The FeSiCr sample treated with 0.2 mol C 3 H 6 N 6 achieves a minimum reflection loss of −54.14 dB at a thickness of 1.5 mm, along with an EAB of 8.01 GHz at 1.7 mm, covering nearly the entire X and Ku bands. Radar cross section (RCS) simulations further confirm the effective microwave absorption performance of carbonitrided FeSiCr. Moreover, carbonitrided FeSiCr shows markedly improved corrosion resistance. When the C 3 H 6 N 6 dosage is 0.2 mol, the corrosion potential reaches 1.17 V, while the corrosion current density decreases to 8.62 × 10 −11 A/cm 2 , indicating good stability in corrosive environments. This study highlights the promising application potential of carbonitriding for microwave absorption.