Corrosion interpretation of the novel rare-element bearing bulk metallic glass: Electrochemical, thermodynamic, and surface analysis of the (Cu50Zr43Al7)100-xErx

Abstract

Bulk metallic glasses (BMGs) have evoked considerable attention in recent years owing to unique properties. However, the surface and anticorrosive properties of this kind of material has not been widely investigated. In this paper, a novel BMG comprises Erbium (Er)-based rare element and high anticorrosive capacity has been introduced. Valorization of Er element (2, 4, 6% at.) in the Cu50Zr43Al7 protective film has been explored from the anticorrosive viewpoint. XRD (X-ray diffraction), GIXRD (Grazing Incidence X-ray Diffraction), AFM (Atomic force microscopy), SEM/EDS (scanning electron microscope/energy-dispersive X-ray spectroscopy), and XPS (X-ray photoelectron spectroscopy) analyses in cooperation with the detailed electrochemical experiments i.e., EIS (Electrochemical Impedance Spectroscopy) and potentiodynamic polarization tests were utilized for surface and corrosion studies. The EIS outcomes have demonstrated that the presence of the Er (at 2% at.) leads to higher corrosion resistance (Rct = 17490 Ω cm2, Rtotal = 7590 Ω cm2) at different time intervals than the other specimens. The proposed mechanism based on surface studies (GIXRD, SEM/EDS, AFM, and XPS) and thermodynamic interpretation imply that the formation of the Er2O3 as a robust protective film along with other types of metal-oxides on the BMG surface is responsible for the high corrosion resistance of this sample.