Pressureless joining of SiC ceramic in oxidizing atmosphere using a SiC nanowires reinforced composite adhesive

Achieving high-temperature-resistant and high-strength connections of silicon carbide ceramics in an oxidizing atmosphere without pressure is an urgent challenge. A composite adhesive was innovatively designed using the polysiloxane as matrix and B 4 C, nano-silicon and LSAM glass-ceramics as fillers. The introduction of LSAM glass-ceramics enabled an excellent matching of the thermal expansion between the adhesive and the SiC. A strong interfacial bonding was formed at the bonded interface due to the dissolution-diffusion of Mg 2+ , Li + , [SiO 4 ] and [AlO 4 ]. Moreover, the SiC nanowires grown in-situ inside the adhesive effectively repaired the defects caused by the pyrolysis of adhesive matrix, substantially enhancing the high-temperature mechanical properties of the SiC joints. After the heat treatment at 1400 °C, the SiC joints bonded using the adhesive showed a room temperature shear strength of 97.2 MPa and a high temperature shear strength of 81.6 MPa at 1300 °C, providing a significant advantage over existing works.