The influence of concentration and pH on corrotion rate in stainless steels – 316 solution HNO₃ medium

The Influence of concentration and pH on corrosion rate on commercial stainless steels-316 materials have been carried out. The experiments were carried out in HNO₃ medium with a concentration variation of 0.1 mol, 0.2 mol, 0.3 mol and 0.4 mol corresponding to pH values of 1.0, 0.7, 0.523, and 0.4 respectively. The experiments were carried out using a type M-273 EG and G galvanometer test instrument. The post-corrosion samples' microstructure has analyzed with the aid of energy dispersive spectroscopy (EDS) equipped SEM instrument to detect the presence of any viable corrosion by products. Experimental results confirm that stainless steels-316 commercial alloys immersed in a nitric acid corrosion medium with a variation of concentration experience very little or almost no corrosion and that according to the so-called Fontana's criteria these test-materials turn out to have an excellent resistance toward nitric acid corrosion. This is also evidenced by the very low corrosion rate value measured in this study. SEM-EDS study, lts indicate that the possible ensuing corrosion by products are iron oxides, and chrome oxides. (paper)