Effect of additional elements on the corrosion behavior of a Cu–Zr–Ti bulk metallic glass

The corrosion resistances of Cu60Zr30Ti10 bulk metallic glass and their derivatives formed by addition of a small amount of Nb, Mo or Ta were evaluated in 1N HCl, 1N H2SO4, 1N HNO3, 1N NaOH and 3% NaCl aqueous solutions by weight loss and polarization curve measurements. Their surfaces were also quantitatively analyzed by X-ray photoelectron spectroscopy (XPS) to clarify the origin of their corrosion resistance. Between Nb, Mo and Ta, addition of Nb was most effective for corrosion resistance in all solutions. It was also found that a metallic glass rod 1.5 mm in diameter was able to be prepared by addition of Nb up to 5 at.%. XPS results revealed that the Zr was enriched by addition of Nb. It was suggested that the role of Nb is to improve the protectiveness of Zr-rich surface film.