Electrochemical corrosion properties of Zr- and Ti-based bulk metallic glasses

The corrosion behaviors of Ti-based and Zr-based amorphous alloys and their corresponding crystallized alloys were studied by electrochemical methods. It is found that the corrosion potentials of Zr-based amorphous alloy and its corresponding crystalline counterpart are both lower than those of the Ti-based amorphous alloy in the 1 mol/L H₂SO₄ solution. In the 3.5 NaCl solution, Zr-based crystallized alloy exhibits the lowest corrosion potential among the experimental samples. No passivation is observed in the corrosion process for the Zr-based crystalline alloy. However, Zr- and Ti-based amorphous alloys both exhibit passivation characteristics. EIS measurements indicate the amorphous alloys exhibit better corrosion resistance than the crystallized one in the NaCl solution. Surface analysis shows that both amorphous alloys in the NaCl solution are eroded by pitting corrosion. In the H₂SO₄ solution, all the alloys display similar behaviors and their surfaces can mostly keep intact except for some cracks on the corroded surface at local region.