Element-resolved electrochemical analysis of transpassive dissolution and repassivation behavior of the multi-principal element alloy AlTiVCr

The dissolution and subsequent repassivation behavior of a lightweight and single-phase multi-principal element alloy (MPEA) AlTiVCr, have been investigated in a quiescent 0.6 M NaCl. The alloy exhibits excellent passivity and repassivation ability in spite of transpassive dissolution of V and Cr during cyclic potentiodynamic polarisation. Elemental-resolved dissolution analysis of the alloy using inline inductively coupled plasma mass spectroscopy (ICP-MS), together with composition analysis of the passive film using X-ray photoelectron spectroscopy (XPS) reveal that the alloy promptly recovers after each transpassive dissolution due to rapid growth of stable TiO2 in the film, which led to a wide passive window. Moreover, the excellent repassivation behavior was found to be due to significant enrichment of Ti on the alloy surface during anodic polarisation. The results, corresponding to the dissolution and compositional evolution of the passive film, were in good agreement with the predicted E-pH diagram of the alloy. (C) 2020 Elsevier Ltd. All rights reserved.