Protection of aluminium alloys from atmospheric corrosion by thin films of inhibitors

Abstract

Some prospects for protection of aluminum alloys by corrosion inhibitors such as carboxylates and trialkoxysilanes are considered. The efficiency of inhibition of anodic dissolution of Al alloys by these compounds in a neutral borate buffer solution containing chlorides (pH 7.4) was investigated. The protective capability of the layers obtained was estimated by an express method (drop test method) and by tests in a heat and moisture cabinet, and in a salt fog cabinet. The efficiency of treatment of Al alloys by aqueous solutions of organic inhibitors was compared with the protective ability of chromate films. It is shown that the passivation of Al alloys by the composition of oleyl sarcosinate with aminoethylaminopropyl-trimethoxysilane at a ratio of 3:1 is an efficient protection method even under salt fog conditions.

Thin Protective Coatings on Metals Formed by Organic Corrosion Inhibitors in Neutral Media

“…The passivation of St3 steel in an aqueous 16.0 mmol/L solution of a SOS and AEAPTS mixture (at their ratio 3:1) and t = 60 • C for 20 min prevents corrosion even under severe conditions of high air humidity and daily condensation. The duration of such protection of steel reaches 456 h, while a similar treatment with a SOS solution itself preserves steel for only 196 h. Interestingly, such passivation has also proven good for other metals, in particular, Al alloys [71].…”