Table 5. Summary of the main outcomes of this study.

Investigation type	Main Outcomes
Surface characterization	Localized corrosion on all the surfaces after the ageing sequence.
	Cu R covered by the most continuous layer of corrosion products and shows the highest O element wt.% increase, due to its strain-hardened microstructure.
	Cu18Ni20Zn is covered by the smallest corrosion spots and undergoes the lowest O increase thanks to its recrystallized microstructure and the presence of alloying elements (i.e., Ni) that enhance its corrosion resistance.
	% variation of Rq: Cu18Ni20Zn (104%) < Cu15Zn (967%) < Cu R+A (1037%) < Cu R (1577%).
	Cu15Zn exhibited the highest increase in Rsk, indicating that localized corrosion products were shaped as relatively high “bubbles”.
	Color variation (ΔE) after ageing: Cu R > Cu15Zn> Cu R+A > Cu18Ni20Zn.
Biofilm inhibition assessment against P. aeruginosa	Strong decrease in biofilm formation capacity on aged Cu alloy surfaces compared to each pristine counterpart.
	Biofilm formation capacity Log10 (CFU/mL/cm2 for aged surfaces)—Log10 (CFU/mL/cm2 for pristine surfaces):
	Cu18Ni20Zn (-0.98) < Cu R (-1.93) < Cu R+A (-2.48) < Cu15Zn (-3.03)
Cu release	Cu release variation due to ageing: Cu18Ni20Zn (1.0x) < Cu R (3.6x) < Cu R+A (8.3x) < Cu15Zn (12.6x).
	Among pristine surfaces: Cu R > Cu18Ni20Zn > Cu R+A ≃ Cu15Zn
	Among aged surfaces: Cu15Zn ≃ Cu R ≃ Cu R+A > Cu18Ni20Zn