Pressureless joining of SiC by molten Si infiltration to the SiC/C filler tape and residual stress analysis

This study examined the joining of monolithic SiC by Si-C reaction bonding using a 100 µm-thick filler tape prepared using different SiC/C compositions (30/70, 50/50, and 70/30 wt%). Joining was performed at 1450, 1500, and 1550 °C for 1 h in a vacuum without pressure after inserting the filler tape followed by molten-Si infiltration. The sample joined at 1500 °C using a SiC/C = 70/30 filler tape revealed a dense joint morphology without pores or cracks, showing the highest joint strength of 254 MPa. A larger amount of SiC in the filler tape resulted in less residual Si at the joining interface and higher joint strength. Moreover, the distribution of residual stresses at the joint was simulated using finite element analysis, which was well-suited to experimental observations based on micro-Raman spectroscopy.