Oxidation resistance and strength retention of laminated G/ZrB2–SiC ceramics

Abstract Laminated G/ZrB 2 –SiC ceramics were prepared by tap-casting and hot-pressing sintering. The effect of adding ZrB 2 and SiC particles into graphite interface layer on the mechanical properties, oxidation resistance and the residual strength after oxidation was investigated. The results showed that the laminated G/ZrB 2 –SiC ceramics, with 40 vol% ZrB 2 and 10 vol% SiC in the graphite interface layer, had a bending strength of 670 MPa at room temperature and fracture toughness of 13.7 MPa m 1/2 . After oxidation at 1500 °C for 10 h, its bending strength still reached 576 MPa and fracture toughness reached 12.7 MPa m 1/2 . The high retention rate of mechanical properties after oxidation was attributed to the dense SiO 2 layer formed on the surface which healed the surface defects and protected effectively the graphite interface layer from oxidation.