Electromagnetic and microwave absorption properties of SiO2-coated Ti3SiC2 powders with higher oxidation resistance

Dense SiO2-coated Ti3SiC2 powders were prepared by the representative Stober route and heat treated process. The phase composition, microstructure, dielectric and microwave absorbing properties of the powders were characterized. XRD pattern reveals the existence of amorphous SiO2 and SEM image shows the SiO2 layer uniformly coated on Ti3SiC2 powders. Both the real and imaginary part of complex permittivity for the SiO2-coated Ti3SiC2 powders decrease due to the insulating SiO2 coating hiders the polarization and electric conductance loss effect. The oxidation resistance of the dense SiO2-coated Ti3SiC2 powders at high temperature was improved. Although the complex permittivity of the powders decrease after oxidized at 600 °C, the dense SiO2-coated Ti3SiC2 powders have larger dielectric constant compared with the bare Ti3SiC2 powders. In addition, the dense SiO2-coated Ti3SiC2 presents better microwave absorption performance after oxidation. The results indicate the dense SiO2 coating can improve oxidation resistance as well as microwave absorption performance of the Ti3SiC2 powders.