Corrosion resistance of crystalline and amorphous CuZr alloys in NaCl aqueous environment and effect of corrosion inhibitors

CuZr alloys are the basis of a family of metallic glasses with large glass forming ability and remarkable mechanical properties. The corrosion response of prepared crystalline and amorphous CuxZr100−x alloys (x = 40, 50, 64 at%), as well as bare Cu and Zr, in a severe corrosive environment, was tested. The alloys were immersed in 3 wt% NaCl aqueous solution. With the aim to increase the resistance of copper as less corrosion alloy component, nine imidazole-based compounds with different functional groups were tested as potential corrosion inhibitors. Potentiodynamic polarization measurements, electrochemical impedance spectroscopy, and long-term immersion tests followed by X-ray photoelectron spectroscopy and microscopy analysis were carried out. Overall, all the tested amorphous alloys exhibit a much better corrosion resistance than their crystalline counterparts in the presence and absence of inhibitors. The main factor controlling the corrosion resistance of the alloys appears to be the Zr-rich (or at least equiatomic) amorphous structure, the effect of the inhibitors being secondary. Results therefore show a complex relationship between inhibitor performance, microstructure and composition of CuZr alloys.