Application of Functional Coating in Delaying the Corrosion of Titanium Alloys: A Review

Abstract

Titanium alloys are utilized in various industries due to their remarkable strength-to-weight ratio, corrosion resistance, and biocompatibility. Nevertheless, their corrosion susceptibility is influenced by temperature, pressure, manufacturing methods, electrolyte properties, mechanical handling, alloy composition, surface passivation, constituent phases, and environmental conditions. Their corrosion resistance is largely determined by the passive film’s density, the chemical composition, and the base metal’s microstructure. These alloys face diverse corrosion challenges in different applications, necessitating the development of effective protective measures. This review examines the types of corrosion, the factors influencing it, and the specific issues encountered in various applications. Furthermore, it provides an overview of using functional coatings to enhance titanium alloys’ corrosion resistance. Based on recent research findings, the review evaluates multiple coatings, including thermal spray coating, chemical vapor deposition, cold spray coating, laser surface engineering, and laser surface alloying. It discusses the protective mechanisms of these coatings, such as barrier formation, passivation, and inhibition of corrosive species. Additionally, challenges related to coating adhesion, durability, and performance under extreme conditions are addressed. This analysis aims to shed light on the current state of functional coatings for titanium alloys and identify potential directions for future research to achieve more robust and durable corrosion protection.