In order to investigate the chemical components which contribute to the corrosion resistance of Type 304 stainless steel in formic acid solution, the natural electrode potential (NEP) variation with time and the anodic polarization curves were measured for pure Fe, Ni, Cr, and Type 304 steel in various concentrations of formic acid solution. Further, in order to investigate the influence of potassium formate as a supporting electrolyte on the corrosion rate of Type 304 stainless steel, the anodic polarization curves and the conventional weight loss test were conducted. It was found that the corrosion behavior in 100% acid solution was quite different from that in the lower acid concentration, and the corrosion rate in aqueous solution was considerably larger than in 100% acid solution. The contribution of Cr to the corrosion resistance of Type 304 stainless steel was observed at potentials below approximately 1.0 V vs SCE (saturated calomel electrode) and that of Fe at potentials above approximately 1.0 V in both aqueous and 100% acid solutions. The corrosion rate was increased with increasing content of HCOOK.

Subject
Noble potential, Acids, Acid concentration, Corrosion rate, Anodic polarization curves, Aqueous solutions, Polarization curves, Formic acid, Steel, Immersion, Corrosion resistance, Electrodes, Electrode potential
National Association of Corrosion Engineers
1984
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