Corrosion behaviors of the iron-based and Ni-based brazing filler metals brazed on the stainless steels in a solution of 3.5mass% NaCl

Abstract

The corrosion resistance was studied electrochemically for an iron-based brazing filler metal F300 and a Ni-based brazing filler metal Ni613. Both austenitic stainless steel SUS316 and ferritic stainless steel SUS444 were used as base metals for these brazing filling metals. F300 showed a higher corrosion rate than those of Ni613 and both base metals and was less corrosion-resistive. While Ni613 showed a stronger depression effect of an anodic reaction than those of base metals, F300 showed little depression effect of the reaction. As an Fe-Ni phase dissolved preferentially in F300 and a finite laminated corrosive morphology was observed, the corrosion progression along a depth direction was suggested. These corrosion behaviors depend on the difference of chemical composition of these brazing filler metals.