Carbothermal reduction reaction enhanced wettability and brazing strength of AgCuTi-SiO2f/SiO2 system

A carbothermal reduction reaction (CRR) approach was developed in this research to tailor the surface phase structure of the SiO2f/SiO2 composites with high chemical reactivity to replace the original inert surface. Results show that SiC can form after CRR treatments. For AgCuTi-SiO2f/SiO2 wetting interfaces, TiC and residual pyrolytic carbon layer can be found inside the reaction layer, which was the key, promoting the wettability of the AgCuTi-SiO2f/SiO2 system. The contact angle of the AgCuTi-SiO2f/SiO2 system dropped from 127 degrees to 43 degrees after the CRR treatments. The reliability of the bonded AgCuTi-SiO2f/SiO2 interface was also characterized by putting 3 different systems into comparison, i.e., the original AgCuTi-SiO2f/SiO2 system, the AgCuTi-SiO2f/SiO2 system with CRR treatments (SiC formation) and the AgCuTi-SiO2f/SiO2 system coated with powdered carbon (no SiC formation). The shear strength of the SiO2f/SiO2-AgCuTi-SiO2f/SiO2 system with CRR treatments was the highest, which was 3 times that of the other 2 brazing systems.