Morpholine as a corrosion inhibitor for aluminium alloys in hydrochloric acid

Abstract

Morpholine was evaluated as an inhibitor for the corrosion of aluminium alloys 2S, 57S and 65S in hydrochloric acid solutions. At 35°, the general order of efficiency was 65S > 57S > 2S. It afforded satisfactory protection to 57S in the temperature range 35–55°, whereas for 2S, its performance is not satisfactory at higher temperatures. It was predominantly a cathodic inhibitor, and reduced the external cathodic current. The difference effect in 2N hydrochloric acid was negative but became positive in the presence of morpholine.