Fabrication of liquid phase sintered SiC materials and their characterization

This paper concerns the liquid phase sintering (LPS) process for the fabrication of SiC based ceramic materials and their characterization. The submicron SiC powder was also utilized for the improvement of LPS-SiC materials. A thermal exposure test was carried out to examine the high temperature stability of LPS-SiC materials. A mixture of Al2O3 and Y2O3 particles was used as an additive in the LPS process. LPS-SiC materials were fabricated by various sintering parameters such as sintering temperature, additive composition ratio (Al2O3/Y2O3) and additive amount (Al2O3 + Y2O3). The strength of LPS-SiC materials was examined at room temperature using a three-point bending test. LPS-SiC materials fabricated at 1820 °C had a density of about 3.1 g/cm3 and a flexural strength of about 780 MPa. However, the strength of LPS-SiC materials substantially decreased after the thermal exposure at 1400 °C for 10 h in the Ar atmosphere, due to the dramatic increase of weight loss by severe erosion.