Electrochemical anodization of stainless steels: Advances in nanostructured oxide synthesis for corrosion-resistant and functional surfaces

• Comprehensive review of anodization of stainless steels for multifunctional oxide formation • Correlates electrochemical parameters with pore morphology and corrosion resistance • Analyzes crystallographic orientation and post-treatment effects on oxide phase stability • Summarizes emerging anodization strategies such as dual-step and plasma-assisted methods • Provides future outlook for integrating anodized stainless steels into energy and catalytic systems The Electrochemical anodization of stainless steels enables the fabrication of nanostructured oxide layers with high corrosion resistance and tunable functionality. Compared with conventional valve metals such as aluminum or titanium, stainless steels present greater complexity due to their multicomponent composition and stable passive films. Recent progress, including dual-step anodization, optimized electrolytes, and targeted post-treatments has made it possible to form robust, self-organized nanoporous oxides with controlled morphology and thickness. This review critically evaluates these advances, highlighting how processing parameters influence oxide composition, pore ordering, and long-term corrosion performance. The discussion integrates recent mechanistic insights with practical design strategies for catalytic, energy-storage, and protective applications. Remaining challenges related to phase stability, mechanical integrity, and scalability are identified, along with future opportunities for deploying anodized stainless steels in advanced electrochemical and energy systems.