Inhibitoren der Korrosion 21 (1) – Autoxidationsstudien an Fe2+-Salzen der Tetramethylen-1,4-bis-phosphonsäure,der Hexamethylen-1,6-bis-phosphonsäure,der Benzol-1,4-bis-phosphonsäure,der Phosphorsäure und Pyrophosphorsäure als Modell einer die Korrosion des Eisens hemmenden Deckschicht

Corrosion Inhibitors 21 (1) – Investigations into the autoxidation of Fe²⁺ salts of tetramethylene-1,4-bis-, hexamethylene-1,6-bis-, benzene-1,4-bis-phosphonic acids, phosphoric acid and pyrophosphoric acid as a model of a surface layer inhibiting the corrosion of iron The efficiency of organic bisphosphonic acids as inhibitors of the corrosion of iron is due to the fact that Fe²⁺ ions leaving the iron surface react with the acid immediately and give rise to the formation of threedimensional surface layers. The more dense the structure of these layers, the more resistant these network is against oxygen and the more resistant to hydrolysis are the Fe? OP bonds, the better the protective effect. Oxygen as well as chloride ions are then prevented excess to the metal surface. The distribution of phosphorus in the precipitates obtained during the model experiments yields information concerning the degree of crosslinking.