Insight into patina formed on beryllium-bronze after 29 years of exposure in an industrial environment and DFT research

This research explores the corrosion behavior of beryllium bronze over a period of 29 years in an industrial atmosphere, revealing an average corrosion rate of 0.557 μm·a−1. The skyward patina layer primarily consists of Cu2O, Cu4SO4(OH)6 and CuSO4, while the field-ward patina layer contains Cu2O, CuO, Cu4SO4(OH)6 and CuSO4. Density functional theory (DFT) calculations and XPS analysis show that Be oxidizes preferentially, providing early-stage corrosion protection. DFT and open circuit potential measurements suggest that the patina layer on the field-ward surface is more thermodynamically stable, but cracks serve as pathways for mass transport, accelerating corrosion.