High temperature characterization of LPS-SiC based materials with oxide additives

This paper dealt with the microstructure and the flexural strength of monolithic SiC and SiCf/SiC composite materials. Especially, the mechanical property of SiC based materials were investigated at the elevated temperatures of 1000 and 1200 °C in the argon atmosphere. The microstructural variation of SiC based materials by the thermal exposure at the bending test temperature was also analyzed. SiC based materials were fabricated by a liquid phase sintering process (LPS), using an additive materials of Al2O3 and Y2O3. A two-dimensional weave of Tyranno SA fibers were utilized as a reinforcing material for SiCf/SiC composite. SiC based materials was sintered at the temperature of 1820 °C for the creation of secondary phases. LPS-SiC materials represented a good density of about 3.1 Mg/m3 and an average flexural strength of about 750 MPa at the room temperature. The sintering density of LPS-SiCf/SiC was also similar to that of LPS-SiC materials. However, the flexural strength of LPS-SiC based materials greatly decreased with the increase of test temperature.