Effect of gadolinium addition on the corrosion behavior and oxide properties of titanium in boric acid solution at 50 °C

Abstract

The purpose of this study is to investigate the electrochemical and immersion corrosion behavior of Ti-5 wt.% Gd alloy in a boric acid solution at 50 °C. The chemical states and defect densities of oxide films formed in the solution were determined using X-ray photoelectron spectroscopy and the Mott–Schottky relation, respectively. Ti-5Gd alloy revealed a higher corrosion and passive current density, and greater weight loss compared to pure Ti, which is primarily attributed to the preferential dissolution of anodic Gd-rich particles in the cathodic Ti matrix. Incorporation of Gd3+ ions into the TiO2 lattice increased oxygen vacancy concentration; therefore, the oxide films of Ti-5Gd alloy contained much more point defects that carry the charges through the films, thereby deteriorating the corrosion resistance of the alloy in regards to the properties of the films.

Keywords

• Ti–Gd alloy
• Gd-rich particle
• Oxide film
• Oxygen vacancy
• Defect density
• Neutron absorbing material