Research status of marine Microbiologically Influenced Corrosion (MIC) Resistant Alloys

This paper focuses on microbiologically influenced corrosion (MIC) resistant alloys, systematically reviewing their current research status and future development directions. It first elucidates the biochemical–electrochemical mechanisms of marine MIC, covering the metabolism of typical microorganisms such as sulfate-reducing bacteria (SRB), the evolution of the biofilm microenvironment, and core mechanisms including cathodic depolarization, extracellular electron transfer (EET), metabolite acid attack/sulfide-induced pitting corrosion, and synergistic damage with chloride ions. The key challenges of multi-factor coupled synergistic corrosion models are also identified. Regarding corrosion-resistant alloying strategies, the microscopic mechanisms of Cu (contact killing and sustained ion release), Cr (passive film self-repair), and rare earth elements (interface purification and inclusion modification) are detailed, along with multi-element synergistic alloy design principles. The effects of heat treatment processes such as solution treatment and aging are analyzed, focusing on how they regulate precipitate phase size and distribution to reduce grain boundary corrosion susceptibility and micro-galvanic corrosion.