Mechanical and X-band dielectric properties of vitrified bonded SiC composites

Abstract

Vitrified bonded SiC composites were prepared from SiC powder and vitrified bond based on B2O3–Al2O3–SiO2–Li2O–Na2O–ZnO system. In the composites, SiC grains were well wetted and coated by the bonding glass, which is observed through a scanning electron microscope. The main crystal structure of the vitrified bonded SiC composites is SiC (3C) and SiO2 phases exist, according to X-Ray Diffraction analysis. The flexural strength of the vitrified bonded SiC composites was investigated and when the content of SiC was 70wt.% it reached up to 71.06MPa. The dielectric properties of the vitrified bonded SiC composites were characterized by the method of vector network analyzer. The real part of the complex permittivity ranges from 5.6 to 9.5 as SiC content changing. The sample incorporating 80wt.% SiC presented the highest dielectric loss tangent. The excellent mechanical and tailored dielectric properties make the vitrified bonded SiC composite a promising candidate for structural microwave shielding materials.