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

SiC_f/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 SiC_f had significant influences on the dielectric and the mechanical properties of SiC_f/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 SiC_f content. In addition, the reinforcement and toughening effects of SiC _f on the composites were also significant. Our results indicate that the SiC_f/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.