AbstractIt is possible by potentiostatic methods to exactly forecast the behaviour of unusual material/corrodent systems; such methods may, consequently, be used for the development of corrosion resistant alloys. A new alloy on iron base (with, %, 25 Cr, 5.5 Ni, 3.0 Cu, 2.5 Mo) combines very good mechanical properties with resistance to general corrosion, pitting and crevice corrosion. Industrial applications include impellers for pumps operating in acid slurries (30% P2O5, 30% CaSO4as solids, 2% H2SO4, HF, H2SiF6; 60–80°C, three years without corrosion); pump impeller for sulfuric acid and other corrosive products shipped in tank ships; impeller for a sea water pump (no corrosion after 4 years' operatio