Comparative Investigation on Corrosion Behaviour of Ni-, Cu- and Co- Based Alloys in Synthetic Mine Water

In an attempt to replace corroding mild steel components in aggressive mine water environ-ments, nickel-chromium-iron (Hastelloy® G30), copper-nickel-tin (ToughMet® 3), and co-balt-chromium-tungsten (Stellite® 6B) hard alloys were selected due to their excellent corrosion resistance, but they remain challenged in many acidic environments. The corrosion behaviours of these alloys were compared and investigated in synthetic mine water with varying pH levels (6, 3, 1) using potentiodynamic polarisation. Microstructural, hardness, and XRD analyses were conducted. Stellite® 6B exhibited superior corrosion resistance across all pH values, outperform-ing both Hastelloy® G30 and ToughMet® 3. With the lowest corrosion rates and comparable high hardness, Stellite® 6B emerges as a promising choice for replacing mild steel pump components in aggressive mine water environments.