Microstructure and corrosion resistance of Ti-Zr-Cu-Pd-Sn glassy and nanocrystalline alloys

The microstructure and corrosion behavior of the Ti_47.5Zr ₁₅Cu₃₀Pd_7.5Sn₅ as-spun ribbons and as-cast rod have been investigated using HREM and potentiodynamic polarization study in simulated body fluids. The results of HREM reveal that, with decreasing cooling rate, the size and volume of nano-particles dispersed in glassy matrix increase for the Ti_47.5Zr₁₅Cu₃₀Pd _7.5Sn₅ as-prepared samples. The as-spun ribbons with small size nano-particle show high corrosion resistance in PBS(-) and Hanks' solution, may be due to the formation of CuZr phase, resulting in the enrichment of Ti and Pd in the glassy matrix, which is helpful to form protective passive film. Comparatively, poor corrosion resistance is observed for the as-cast rod sample with larger nano-particles in both solutions.