Interfacial Si–O coordination for inhibiting the graphite phase enables superior SiC/Nb heterostructure joining by AuNi

The reaction between SiC and Ni-based brazing alloy is extremely intense, where the brittle Ni–Si compound and accompanied dissociate graphite phase as the interfacial reaction product in the joint damage the mechanical properties. In this study, the design of "graphite-controlled" heterogeneous integration component structure on SiC surface is developed to weaken the intense reaction of Ni and SiC. The high-quality surface Si–O coordination was successfully achieved by plasma-enhanced chemical vapor deposition (PECVD) method at relatively low temperature on SiC, which increases the Si bond strength due to that the higher binding energy of Si–O (451 kJ/mol) than that of Si–C (347 kJ/mol). SiO2 films enhance the mechanical properties of the joint through macro-weak side interface interlocking and micro-stress mismatch regulation. The shear strength of SiC/Nb heterostructure joints by AuNi alloy was increased by 44 %, which paves an inspiring way for boosting heterogeneous integration of SiC ceramic components.