Joining of High Damage Tolerant SiC Fabric to High Strength SiC

Abstract

SiC fabric layers including Al₂O₃ or Al₂O₃–mullite particles were joined to the oxidized dense SiC compact through the SiC/Al₂O₃ or Al₂O₃/mullite intermediate layers. The thickness of SiO₂ layer formed on the oxidized SiC surfaces is a key factor to control the joining. The laminate of SiC fabric / SiC-Al₂O₃ sheet or SiC fabric / Al₂O₃ –mullite sheet showed high damage tolerance to the surface cracks. The fabric layers prevented the propagation of cracks formed. Joining under a low applied pressure (< 2 MPa) was recommended to maintain the high strength of inside SiC compact. Increased pressure during the joining caused the creep rupture of inside dense SiC compact.