Effects of concentration and temperature on corrosion resistance of nickel base alloys in acidic environments

摘要

The corrosion resistance of three nickel base alloys, Inconel alloys 600 and 601 and Nickel-201, hasbeen studied in 0.01-10M H{sub}2SO{sub}4 at 30, 60, and 90℃. Open circuit potential (OCP)measurements at 30 ℃ indicated the attainment of a positive OCP for alloy 601 in all concentrationsof acid except in 10M H{sub}2SO{sub}4, while alloys 600 and 201 showed negative OCP valueseven in 0.01M H{sub}2SO{sub}4. A further negative shift in OCP was recorded for alloys 600 and201 at 60 and 90℃. However a positive shift in OCP was noted for alloy 601 in 10MH{sub}2SO{sub}4 at 60 and 90℃. Corrosion current measurements indicated better corrosionresistance for alloy 601 than for alloy 600, whereas alloy 201 showed poor corrosion resistance in allconcentrations of acid. Alloy 601 showed spontaneous passivation from the corrosion potential in0.01 - 1.0M H{sub}2SO{sub}4 at 30 ℃ during potentiodynamic polarisation. In contrast, alloys600 and 201 exhibited I{sub}crit - I{sub}pass transitions before the onset of passivation in allconcentrations of acid at all experimental temperatures.