Insight into the corrosion inhibition performance of triethylenetetramine (TETA) for AZ31 Mg alloy

Abstract

As the lightest engineering material, Mg alloys have tremendous application prospects. However, due to their high reactivity, they are highly susceptible to corrosion. Traditional organic corrosion inhibitors have limited effectiveness in protecting Mg alloys, making it difficult to provide excellent protective performance. To address this, our project has discovered an extremely efficient corrosion inhibitor, Triethylenetetramine (TETA), and conducted in-depth research on its protective performance and mechanism. Corrosion electrochemical tests indicated that at a TETA concentration of 47 mM, the inhibition efficiency after 24 hours of immersion in 3.5 wt% NaCl was 98.8 %, and 99.7 % while switched to 0.1 M NaCl. SEM surface morphology analysis showed that the Mg alloy surface remained smooth with no significant corrosion features after adding TETA. XPS surface chemical analysis revealed that the protective TETA layer on the Mg alloy surface was formed due to the adsorption of polar groups. FT-IR technology further confirmed the successful adsorption of TETA. Experimental and theoretical calculations indicate that the corrosion protection mechanism of TETA is due to the spontaneous adsorption of TETA, which forms a dense protective film.