Effect of water content on the corrosion behaviour of type 430 stainless steel in formic and acetic acids

✍ Scribed by Isao Sekine; Shuichi Hatakeyama; Yuji Nakazawa

• Publisher: Elsevier Science
• Year: 1987
• Tongue: English
• Weight: 546 KB
• Volume: 32
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(87)87083-4

✦ Synopsis

Corrosion of Type 430 stainless steel was studied in the formic acid-water and in the acetic acid-water systems. Weight-loss measurements were made at ambient temperature and at the solution boiling points. Corrosion rates depended strongly upon solution concentration and upon temperature; in particular, higb corrosion rates were observed at the boiling point of 100% acetic acid. This enhanced corrosion did not occur under corresponding conditions in the formic acid system. The conductivity of 100 % acetic acid was found to increase remarkably with temperature in contrast to experimental conductivity-temperature relations observed for other aqueous acetic acid and formic acid solutions. On the basis of surface analysis techniques, Cr,OJ, Fe0 and Fe,O, exist in the surface layer formed when Type 430 stainless steel is exposed to boiling acetic acid, however, only a small amount of the protective compound Cr,O, is present. The high conductivity of acetic acid at its boiling point and the Cr,Os content of the surface layer, are used to explain high corrosion rates.