単一成分および多成分有機溶液中における軟鋼の腐食挙動

抄録

The corrosion behavior of SS 400 (mild steel) was investigated in one component system of pure organic solvents (acetic acid, ethanol, diethylamine and acetone) and multi-component system of organic solutions containing additive agents (water, lithium perchlorate, sulfuric acid and nitric acid) by the corrosion weight loss tests, electrochemical measurements and surface analyses. From these results, the corrosion of mild steel was remarkably promoted by sulfuric acid and nitric acid in organic solutions. The corrosion rate increased in strong basic solvent (ethanol), and decreased in weak basic solvent (acetic acid) by addition of sulfuric acid. The passive state region was observed in wide potential range on anodic polarization curves, and the rest potential existed in passive state region in non-corrosion systems. In a.c. impedance measurements, the charge transfer process was observed in remarkable corrosion systems, and the film resistance of passive state was increased in non-corrosion systems. In surface analysis by XPS, the salt film of acetate on steel surface was observed in acetic acid of corrosion system, while the passive film made up by adsorption of solvent molecules and the oxides was observed in ethanol or acetone of non-corrosion systems.