Effect of pH on the polarization behavior of Zr65Al7.5Ni10Cu17.5 amorphousalloy in a phosphate-buffered solution

For the biomedical use of amorphous alloys, the effect of pH on the polariz ation behavior of Zr65Al7.5Ni10Cu17.5 amorphous alloy was evaluated in phos phate-buffered solutions with and without chloride ion. In the solution wit hout chloride ion, the corrosion resistance at open-circuit potential decre ased with a decrease in pH. The open-circuit potential was ennobled with a decrease in pH by the acceleration of a cathodic reaction. However, the ope n-circuit potential was not changed by chloride ion, and the pitting potent ial was not changed with the decrease in pH. Then, the open-circuit potenti al was always less noble than the pitting potential. Therefore, the pitting -corrosion resistance of the zirconium-based amorphous alloy decreases with a decrease in pH due to the shift of the open-circuit potential. However, pitting corrosion does not occur spontaneously with a decrease in pH, (C) 2 000 Elsevier Science Ltd. All rights reserved.