Corrosion resistance of crystalline and amorphous CuZr alloys in NaCl aqueous environment and effect of corrosion inhibitors
Chenyang Xie, Ingrid Milošev, Frank Uwe Renner, Anton Kokalj, P. Bruna, Daniel Crespo
Abstract
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.