The inhibition effects of Cu and Ni alloying elements on corrosion of HSLA steel influenced by Halomonas titanicae.

Abstract

Halomonas titanicae accelerated steel corrosion by dissimilatory Fe(III) reduction under anaerobic environments, and their adhesion was the key to achieving extracellular electron transfer between cells and Fe(III). This work investigated the inhibition effects of Cu and Ni alloying elements on corrosion of high strength low alloy (HSLA) steel affected by H. titanicae. It was found that both the addition of Cu (1.3%) and high content of Ni (7.2%) brought better corrosion resistance than the steel containing 4.8% Ni via decreasing the amount of sessile bacterial cells. And the inhibition efficiency of Cu with the lower content was stronger than that of Ni with the higher content. Biofilm inhibition mechanisms varied from Cu to Ni alloying elements, and the former was achieved via bactericidal Cu ions released from steel. While for the HSLA steel with high Ni content, the formation of nickel oxides including NiFe2O4 and Ni(OH)2 refined the grains of corrosion products and decreased the bacterial attachment.