Homogenized joining of SiC ceramics using polycarbosilane via spark plasma sintering

The low coefficient of thermal expansion of SiC ceramics poses a significant challenge in selecting a compatible filler material for achieving high-quality joints. In this study, a composite adhesive was developed by blending vinylhydridopolycarbosilane (VHPCS) with nano-sized SiC particles to facilitate the pre-joining of SiC ceramics at 200 °C. The pre-assembled structures were subsequently joined using spark plasma sintering. The joining mechanism involves the use of VHPCS as an interlayer medium, where the application of elevated temperature and pulsed electric current promotes interfacial bonding between the joining layer and the SiC substrate. As a result, a homogeneous SiC ceramic joint, structurally compatible with the substrate, was successfully formed at 1700 °C. This approach provides a reliable joining technique for expanding the application of SiC ceramics in extreme environments.