2023 Volume 62 Issue 1 Pages 105-109
In this study, we focused on the fact that the solidification structure of brazing filler metals varies depending on its composition and cooling rate, and investigated the effect of the cooling rate during brazing on the relevant corrosion based on the metallurgical structure and corrosion behavior measured by polarization curves. The results showed that the metallurgical structure became finer in the air cooled and ice water cooled the filler metals than in the furnace cooled the filler metals. The microstructure was considered to be two phases of Cu solid solution with Sn and P solid solution and Cu3P for the filler metal A, and three phases of Cu solid solution with Ag and P solid solution, Ag solid solution and Cu3P for the filler metal B. Compared to furnace cooling, air cooling was considered to improve the corrosion resistance of the filler metals because Sn and Ag ware finely dispersed throughout the filler metals due to the finer microstructure, while copper base metal corrosion progresses.
