Characterization of brazed joints by electrical resistance spot brazing with Ni-based amorphous self-flux alloys

In this study the behavior of brazing joints with nickel-silicon-based amorphous alloys ribbons was analyzed in terms of mechanical strength and corrosion resistance. Two Ni78Si8B15 and Ni68Fe3Cr7Si8B14 metallic glasses ribbons designed and fabricated in our laboratory have been studied as brazing foils. The base material of the joint is the 316L austenitic stainless steel. Note that the two tested chemical compositions of the ribbons are recommended for brazing stainless steels. A comparison between brazed joints and welded steel by electrical resistance spot has also been conducted. As results, Ni78Si8B15 amorphous alloy presents a very good castability, wettability and flowability. However the addition of chromium and iron to form Ni68Fe3Cr7Si8B14 significantly increases the melting temperature, the corrosion resistance and the mechanical strength. Finally we found that the brazed joint with Ni68Fe3Cr7Si8B14 metallic glasses ribbon has the same yield strength than that of the welded joint, but it presents a better corrosion resistance.