Nano-infiltration and transient eutectic (NITE) phase joining SiC ceramics at 1500°C

By using nano-infiltration and transient eutectic (NITE) phase with nanosized SiC and the addition of CeO2-Al2O3 as joining material, liquid-phase-sintered SiC ceramics were joined at the relatively low temperature of 1500 degrees C and 1700 degrees C. For comparison purpose, Al2O3-Y2O3 and SiO2-Al2O3-Y2O3 were used as the additives to join SiC ceramics. The shear strength of SiC assembly with the interlayer thickness of similar to 70 mu m and addition of CeO2-Al2O3 after joining at 1700 degrees C was measured to be 163.9 MPa but decreased to 57.4 MPa when joining at 1500 degrees C. It was revealed that the joining status could be improved by decreasing the thickness of the interlayer to similar to 35 mu m and SiC joint finishing at 1500 degrees C possessed the comparatively high shear strength of 113.2 MPa. NITE phase containing other additives (Al2O3-Y2O3 and SiO2-Al2O3-Y2O3) showed the much lower shear strength after joining at 1500 degrees C.