Advances in Anticorrosion and Anti-wear Plasma Electrolytic Oxidation Coatings for Titanium and Its Alloys

Plasma electrolytic oxidation (PEO) has emerged as a promising surface modification technique for enhancing the corrosion and wear resistance of titanium and its alloys. Titanium, widely used in aerospace, biomedical, and industrial applications, possesses excellent corrosion resistance but suffers from poor tribological performance in demanding environments. PEO creates a hard, ceramic-like oxide layer with a multilayered microstructure that provides superior protection against mechanical wear and electrochemical degradation. This chapter explores recent advances in anticorrosion and anti-wear PEO coatings for titanium, emphasizing process optimization, electrolyte innovations, and posttreatment strategies. The influence of alloying elements, substrate pretreatment, electrical parameters, and advanced electrolyte formulations on coating microstructure and performance is discussed. Additionally, emerging hybrid and duplex coating approaches and self-lubricating additives are examined for their potential to further enhance durability. The synergy between wear and corrosion mechanisms, tribocorrosion behavior, and long-term performance assessments are analyzed to provide a comprehensive understanding of PEO-coated titanium in real-world applications. Finally, key research gaps and future directions, including AI-driven process optimization, smart coatings, and additive manufacturing integration, are highlighted to guide advancements in this field.