Corrosion performance of naval brass in a simulated ocean water environment under different aqueous conditions

This study assesses the corrosion response of naval brass (NB) (Cu-39.0Zn-1.0Sn-3.5Pb wt.%) with ocean water salt mixture added in distilled water (DW), tap water (TW), and 50%Tap water + 50%Rain water (TW + RW) conditions. The NB in DW exhibited reduced weight loss and corrosion rate compared to TW and TW + RW conditions, which was maximum in TW condition. The electrochemical corrosion rates increased to 168 h and declined at 336 h, with higher corrosion rates witnessed in TW and lowest in DW conditions. The corrosion rate after 168 h in TW was 32 % higher than in DW condition. The corrosion products on NB include cuprite, atacamite, brochantite, and simonkolleite, more prevalent in TW conditions. The dezincification was minimal in DW but increased in TW and TW + RW conditions, peaking in TW condition. Pit number and size were smaller in DW but larger in TW and TW + RW conditions, with TW exhibiting the most extensive and deeper pits, indicating heightened corrosion from localized Zn dissolution. Zn removal from alpha and beta ' phases was lower initially in DW while escalating in TW and TW + RW conditions over time. The NB in the TW condition showed prominent Zn removal than in DW condition, especially after 336 h.