Investigation of interfacial bonding between Na2O-B2O3-SiO2 solder and silicon carbide substrate

The interfacial characteristics of the SiC/glass solder/SiC joining part were investigated by means of thermodynamic and wetting behaviour calculation, microstructure observation, chemical structure and element analysis. The results of wavelength dispersive spectroscopy linear scan across the joint showed a relatively low increase in sodium content at the interfaces, which indicated that the sodium silicates in glass could react with silicon carbide substrate at the joining temperature, but it is not the reason for the good bonding between SiC and the interlayer. The mechanism of the good interfacial bonding lies in the formation of oxycarbide phase at the interface.