Reaction synthesis of mullite-silicon carbide-yttria-stabilized zirconia composites

摘要

SiC/mullite/zirconia composites were fabricated by controlling the oxidation of powder compacts of SiC, alumina, and 3 mol yttria-stabilized zirconia. The powder compacts were first oxidized in air at l l00 deg. C for various times to obtain proper amounts of amorphous silica. Subsequent reaction sintering at l500 deg. C for 2 h combined the amorphous silica with alumina to form mullite with planned amounts. The incorporation of 3 mol yttria-stabilized zirconia promoted mullite formation and enhanced the densification of the samples. With ≥ l0 vol of 3 mol yttria-stabilized zirconia in the samples, the temperature of mullite formation was lowered from l400 to 1300 deg. C, and mullitization was near completion after sintering at 1500 deg. C for 2 h. The densification of the samples depended on the contents of SiC and 3 mol yttria-stabilized zirconia. Samples with 20 vol SiC and l0-20 vol 3 mol yttria-stabilized zirconia could be sintered to reach approximately 97 of theoretical density after sintering at l500 deg. C for 2 h.