Corrosion inhibition of steel in phosphoric acid

Abstract

Abstract Phosphoric acid has been used in many industrial applications and can be in contact with a lot chemical and petrochemical equipment. Most of this equipment is made of steel alloys that may be damaged because of contact with acid. Corrosion inhibitors can be used for to protect steel alloys against several forms and various environments of corrosion. In this paper, the efficiency and applications of organic and inorganic inhibitors in different environments of phosphoric acid are investigated. More than 40 papers were collected and reviewed. Surveys of the stated works in phosphoric acid environments are documented. It was concluded that organic inhibitors performed as good corrosion inhibitors and are used widely. The use of inorganic inhibitors was limited. Most of studied inhibitors follow Langmuir’s adsorption isotherm, and the mechanism of the inhibition can be ascribed to the mixed effect on cathodic and anodic reactions. The synergistic effect was also addressed in the present work.