Dielectric and microwave absorption properties of FexCoyP-loaded porous Al2O3 composites

Transition-metal phosphides have been investigated for microwave absorption applications owing to their excellent conduction loss and magnetic property. In this study, novel composites comprised of porous Al2O3 matrix loaded with FexCoyP (FexCoyP/Al2O3) were prepared by vacuum impregnation, hydrothermal, and low -temperature phosphatizing methods. The experimental results show that FexCoyP is uniformly deposited on the surface of porous Al2O3 ceramic, and the FexCoyP transforms from needle-like to particle-like structures as the Fe/Co ratio increases from 1:3 to 3:1. The minimum reflection loss (RLmin) of FeCo3P/Al2O3 composite reaches-26.19 dB at 12.4 GHz with a matching thickness of 2.6 mm, and the maximum effective absorption bandwidth (EAB) achieves 4.2 GHz in the whole X-band at 3.2 mm thicknesses. This study confirmed that the porous FexCoyP/Al2O3 composites are potential candidates for microwave absorption applications, and their microwave absorption properties can be enhanced by adjusting the ratio of Fe to Co.