Joining of Ti-coated monolithic SiC using a SiCw/Ti3SiC2 filler by electric field-assisted sintering

Abstract

Monolithic SiC, for the first time, was successfully joined using a SiC whisker-reinforced Ti3SiC2 composite (SiCw/Ti3SiC2) filler via electric field-assisted sintering technique. A thin Ti coating layer was formed on the SiC surface to minimize the residual stress at the joint interface by transforming it into a TiC gradient layer. After optimizing process parameters, a joint strength higher than 250 MPa was obtained, which is higher than the other values reported in the literature. Failure occurred at the SiC base rather than the joining interface because of the improved joint strength by the incorporation of SiCw. The addition up to 15 wt. % SiCw in the filler layer improved the joint strength by various strengthening mechanisms. On the other hand, the joint strength was lower with 20 wt. % SiCw addition, indicating the importance of thermal expansion mismatch between SiCw and Ti3SiC2 to obtain a sound SiC joint.