Influence of short carbon fiber content on mechanical and dielectric properties of Cfiber/Si3N4 composites

Cfiber/Si3N4 composites were prepared by hot-pressed sintering using α-Si3N4 powders, short carbon fibers and sintering additives as starting materials. The mechanical and dielectric properties of these composites were studied. When the short carbon fiber content of the composites increases from 0 to 1 wt.%, the fracture toughness increases from 3.456 to 4.203 MPa m1/2, and both the real and imaginary part of permittivity increase greatly over the frequency range 8.2–12.4 GHz. These effects were due to the anisotropy of short carbon fibers.