SiO2-modified Y2Co8Fe9 multifunctional alloys with efficient microwave absorption, oxidation resistance and corrosion resistance

Abstract

The application of a single metallic magnetic absorbing materials in harsh environments such as high temperature and corrosion reduces its absorption capacity significantly. Therefore, it is urgent to develop multifunctional composite materials with good absorption properties, oxidation resistance and corrosion resistance. In this work, SiO2-modified Y2Co8Fe9 (YCF) alloys with tunable tetraethyl orthosilicate content are prepared by the Stӧber method. The SiO2 coating efficiently enhances the microwave absorption properties due to the improved impedance matching characteristics. The SiO2 coating also provides effective physicochemical protection to prevent the alloys from oxidation and corrosion. Importantly, the YCF@SiO2-6 composite possesses enhanced microwave absorption properties with a minimum reflection loss (RLmin) of − 58.5 dB at 12.46 GHz with a thickness of 1.5 mm. The starting oxidation temperature of the YCF@SiO2-6 composite was 280 ℃ and 50 ℃ higher than that of the YCF and YCF@SiO2-2 samples, respectively. In addition, the corrosion resistance of the YCF@SiO2-6 composite in 3.5 wt% NaCl solution and hot and humid environment was tested by two different methods. The results indicate that the SiO2-modified sample shows good corrosion resistance. Therefore, this research provides a simple and practical method for the preparation of multifunctional composites in the field of electromagnetic wave absorption.