Microbiologically influenced corrosion (MIC) of stainless steel 304 and copper-nickel alloy (70:30) and its inhibition in seawater environments

Abstract

Microbiologically influenced corrosion (MIC) is extremely harmful to maritime industries and to the environment, as approximate 20% of corrosion is estimated to be caused by MIC. This study was carried out to investigate the roles of microorganisms in the aerobic and anaerobic corrosion processes of stainless steel 304 and copper-nickel alloys (70:30) in simulated seawater environments. Results showed that the two metal coupons both underwent severe deterioration under the attack of aerobic Pseudomonas NCIMB 2021 and anaerobic Desulfovibrio desulfuricans (ATCC 27774) bacteria, in the forms of extensive pitting corrosion, thus leading to the acceleration of corrosion rate. On the basis of MIC study, two novel surface modification techniques were developed to minimize MIC of metals: one is to impart the metallic substrate with bactericidal and anticorrosive properties by developing a bilayer of organic coatings, and the other is to buildup highly-resistant multilayers of Ti oxide/butoxide coatings using layer-by-layer sol-gel process.