Corrosion and High Temperature Oxidation Behavior of 316L Stainless Steel Joined with Cu-Ag Based Braze Alloys
316L samples of various geometries were joined under Argon atmosphere using Cu-Ag based braze alloys. Following joining, elemental and phase composition across the braze and parent metal interface was characterized with optical microscopy and SEM with EDS. Baseline electrochemical testing was performed on each of the braze alloys in the fired and unfired condition. Additionally, metal-to-metal braze specimens were prepared in order to expose the braze interface to 0.6 M NaCl electrolyte where the free corrosion potential was monitored. Following exposure to the aggressive solution, the corrosion damage morphology was characterized to determine the mode of attack and likely initiation areas. The critical potential for localized corrosion initiation was also investigated for the braze alloys when connected galvanically to 316L samples to determine the impact of brazing on localized corrosion. Initial results indicate dissimilar metal driven corrosion attack at the braze metal interface into the parent 316L as well as preferential dissolution of the Cu rich phase within the braze alloy when exposed to 0.6 M NaCl.
Hurley, Michael F.; Knori, Kyle; Jaques, Brian J.; Butt, Darryl P.; Elsentriecy, Hassan; and Shoeib, Madiha. (2012). "Corrosion and High Temperature Oxidation Behavior of 316L Stainless Steel Joined with Cu-Ag Based Braze Alloys". 5th International Brazing and Soldering Conference, .