Dielectric and mechanical properties of hot-pressed sintered C _sf/Al ₂O ₃ ceramic composites

High densified C _sf/Al ₂O ₃ ceramic composites were prepared by hot-pressed sintering using α-Al ₂O ₃ powders and short carbon fibers as starting materials. Dielectric and mechanical properties of these composites were evaluated. The results show that the addition of short carbon fiber (C _sf) conducting fillers renders the composites radar absorbing ability, while the hardness around 90 HRF and strength around 300 MPa are also obtained in these composites. Both the fiber content and the length can be used to optimize the dielectric property at the frequency range 8.2-12.4 GHz. The results indicate that C _sf/Al ₂O ₃ composite is a promising radar absorbing material with load-bearing ability.