Interfacial microstructure and improved wetting mechanism of SiO2f/SiO2 brazed with Nb by plasma treatment

Plasma treatment can coat thin carbon film and form C-Si bonding on the surface of SiO2f/SiO2, which both show good wettability with AgCuTi. Therefore, the contact angle was notably reduced from 131° to 45° with only 5min plasma treatment on the SiO2f/SiO2. Afterwards, the effect of plasma treating time on the interfacial microstructure and mechanical property of SiO2f/SiO2-Nb joints were investigated in detail. It was found that adjusting the plasma treating time can control the distance of brazing alloy infiltration. Further, the shear strength and the fracture morphologies were closely related with the distance of brazing alloy infiltration. The infiltration of AgCuTi at the SiO2f/SiO2 side can significantly increase the bonding areas and reduce residual stress, and thus enhance the mechanical properties of brazed joints.