Research progress on the corrosion behavior of titanium alloys

Abstract

Titanium and its alloys show outstanding application prospects in many industrial fields due to their high specific strength, good corrosion resistance, high temperature resistance, etc. However, at present the corrosion failure of Ti alloys is attracted great attention with gradual increasing applications. The different localized corrosion forms are introduced in this review, including galvanic corrosion, crevice corrosion, pitting corrosion, hydrogen-induced cracking, stress corrosion crack, microbiological corrosion, corrosion fatigue, and corrosion wear. Among them, the corrosion failure caused by stress corrosion crack and hydrogen-induced cracking is the most serious, accounting for about 40–60% of the actual failure accidents. The effects of temperature, pressure, corrosive media and microstructure on the failure of titanium alloys are discussed. Particularly noteworthy, F− is extremely aggressive to the passive film of titanium alloys. The corrosion behavior of titanium alloys applied in aerospace, marine, petrochemical industries and biomedical environments are introduced. In the above environments, the passive film is most easily damaged and difficult to passive in high temperature and oxygen-deficient environments. The current controversies in the corrosion mechanism have also been proposed, especially the stress corrosion that has the most serious impact on titanium alloys, and its mechanism will be the focus of future research.

Molecular Insights into the Stability of Titanium in Electrolytes Containing Chlorine and Fluorine Ions

“…This phenomenon is consistent with the experimentally observed stronger erosivity of F − . 14,16,45 Moreover, the coadsorption of protons further reduces the work function of the titanium passive film. Among them, the coadsorption of protons on the anatase surface reduces the work function of the Cl − -and F − -adsorbed surfaces to 6.74 and 6.38 eV, respectively, indicating a greater impact on the work function of the F − -adsorbed surface.…”

“…The titanium passive film can be corroded by F – and resist Cl – in a neutral environment at room temperature. − ,,, As these are two of the most common anions in seawater, it is crucial to investigate their adsorption behavior on a titanium surface to understand the passive film stability in an aqueous electrolyte system, regardless of whether it is in the film repassivation or stabilization stage.…”

“…The speculated possibility is that Cl – forms Ti–Cl and Ti–O complexes on the passive film surface, while the Ti–F compound exhibits a stronger corrosion effect. Under an acidic electrolyte solution containing F – , titanium atoms tend to dissolve as TiF 6 2– or TiF 6 3– after the passive film is degraded . However, the above speculation is still based on the inference of macroscopic electrochemical testing, ,− lacking molecular and electronic evidence.…”

“…2− or TiF 6 3− after the passive film is degraded. 16 However, the above speculation is still based on the inference of macroscopic electrochemical testing, 14,17−19 lacking molecular and electronic evidence. Thus, more fundamental research is needed to understand the underlying mechanisms of film formation, stability, and dissociation, which all have a significant effect on the corrosion behavior of these materials.…”

Corrosion fatigue behavior of continuous gradient porous Ti‐15Mo alloy prepared by selective laser melting

“…The phenomenon of corrosion fatigue is a result of the combined effects of cyclic loads and corrosive media, as noted in Yang et al 47 Notably, materials exhibit increased susceptibility to environmental factors at lower load levels. 47 Titanium alloys naturally develop a robust passivating oxide layer in the presence of oxygen. 48 The presence of this passive film contributes to the excellent corrosion resistance exhibited by titanium alloys.…”