Short-carbon-fiber reinforced alumina ceramic with improved mechanical property and dielectric property in the Ku-band

摘要

Short carbon fibers (C_(sf) reinforced alumina composites were prepared by a hot-pressing sintering process. The influences of C_(sf) content and liber length on mechanical and dielectric properties of the composites in the Ku-band (12.4-18 GHz) were evaluated. The flexure strength of the ceramic increased with the C_(sf) incorporation and the maximum value of 475 MPa was obtained bv the addition of 0.3 wt% C_(sf) with the length being 2 mm. The electronic polarization relaxation is contributed to the variation of the real pan of the permittivity (ε') with increasing C_(sf) content and fiber length. The associated polarization relaxation and conductivity of the composites are responsible for the variation of the imaginary part (ε"). When 0,1 wt% C_(sf) with length of 4 mm was incorporated, the reflection loss below -6 dB can he obtained in the Ku-band with the coating thickness being 1.2 mm. The results indicate that C_(sf)-Al_2O_3, composite could be a potential microwave absorbing material used in the Ku-band.