Enhancing the Corrosion Resistance of Cu–Fe Alloy by Trace Yttrium Addition

The poor corrosion resistance of Cu–Fe alloys, caused by the intrinsic galvanic coupling between the Fe‐rich phase and the Cu matrix, restricts their wider application. In this work, the effect of trace yttrium (Y) addition on the microstructure and corrosion behavior of a Cu–5Fe alloy was systematically investigated. The results demonstrated that the addition of 0.016 wt% Y significantly enhanced the corrosion resistance of the alloy.Quantitatively, the 0.016 wt% Y addition reduced the 28‐day cumulative weight loss in 3.5 wt% NaCl solution from 40.0 to 19.8 g/m 2 , and decreased the corrosion current density from 11.25 to 1.91 μA/cm 2 . Mechanistically, Y addition modified the precipitation behavior of Fe during the cooling process, effectively suppressing the formation of secondary Fe precipitates within the Cu matrix and reducing the density of micro‐galvanic couples. Furthermore, Scanning Kelvin Probe Force Microscopy (SKPFM) analysis revealed that Y reduced the Volta potential difference between the Fe particles and the Cu matrix from 26.8 to 13.5 mV, thereby weakening the thermodynamic driving force for galvanic corrosion. These synergistic effects promoted the formation of a dense and protective oxide film, leading to superior corrosion inhibition performance.