Corrosion Characteristics of Aged CuCrZr Alloys Manufactured by Gravity Die Casting in a Chloride Salt Bath Environment

Abstract The corrosion characteristics of CuZrCr (CZC) alloys produced by gravity die casting and aged at 500 °C for varying durations (0, 0.5, 1.0, and 1.5 h) were investigated in a chloride salt bath environment. Corrosion behavior was assessed in a 50KCl–50NaCl molten salt mixture at 450 °C using the weight loss method, while electrochemical techniques, potentiodynamic polarization, and electrochemical impedance spectroscopy were applied at room temperature. Vickers hardness testing was conducted on uncorroded samples, revealing hardness values that varied with microstructural changes induced by aging. The highest hardness (129.8 HV) was observed in the CZC 1.5A alloy, while initial aging (0.5 h) led to softening, followed by re-hardening at longer durations. Corrosion rate (CR) results exhibited a complex dependence on both alloy composition and aging time. Surface and compositional analyses using SEM-EDX showed increased oxygen and salt element uptake in aged samples, indicating more pronounced oxidation and chloride penetration, which correlate with the deterioration of passive film stability.