Influences of SiCf content and length on the strength, toughness and dielectric properties of SiCf/LAS glass-ceramic composites

SiCf/LAS glass-ceramic composites were prepared by hot-press sintering using SiC fibers, SiO2, Al2O3 and Li2CO3 powders as starting materials. Mechanical properties, such as strength, toughness, and dielectric properties at X-band microwave frequency of these composites were evaluated. Results showed that both the content and the length of SiCf had significant influences on the dielectric and the mechanical properties of SiCf/LAS composites. The complex permittivity of the composites rose from 12 to 35 for ε′ and 18 to 120 for ε″ at 8.2 GHz with the increasing SiCf content. In addition, the reinforcement and toughening effects of SiCf on the composites were also significant. Our results indicate that the SiCf/LAS composite is a promising material with both the electromagnetic wave absorbing and the load-bearing abilities suitable as structural microwave absorbing and microwave shielding materials.