Carbothermal reduction reaction enhanced wettability and brazing strength of AgCuTi-SiO_2f/SiO₂ system

A carbothermal reduction reaction (CRR) approach was developed in this research to tailor the surface phase structure of the SiO_2f/SiO₂ composites with high chemical reactivity to replace the original inert surface. Results show that SiC can form after CRR treatments. For AgCuTi-SiO_2f/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-SiO_2f/SiO₂ system. The contact angle of the AgCuTi-SiO_2f/SiO₂ system dropped from 127° to 43° after the CRR treatments. The reliability of the bonded AgCuTi-SiO_2f/SiO₂ interface was also characterized by putting 3 different systems into comparison, i.e., the original AgCuTi-SiO_2f/SiO₂ system, the AgCuTi-SiO_2f/SiO₂ system with CRR treatments (SiC formation) and the AgCuTi-SiO_2f/SiO₂ system coated with powdered carbon (no SiC formation). The shear strength of the SiO_2f/SiO₂-AgCuTi-SiO_2f/SiO₂ system with CRR treatments was the highest, which was 3 times that of the other 2 brazing systems.