Q. Define corrosion-resistant nickel-based alloys?
The corrosion-resistant nickel-based alloys offer a significant improvement in corrosion resistance to sulphuric acid over the 300 series stainless steels. A broader range of concentrations can be handled; however, temperature is still a limiting factor.
A number of corrosion resistant nickel alloys are commercially available. The Iso-Corrosion Charts for several common alloys. Each alloy typically has its own advantages. In selecting a specific alloy for a given service, some in situ corrosion testing is recommended.
Alloy-20 (Carpenter 20Cb3) and Incoloy 825 are two readily available commercial nickel-based alloys that have superior corrosion resistance to a broad range of H2SO4 concentrations. Higher nickel-based alloys, such as Hastelloy B, Hastelloy C / C276 and Hastelloy G, also offer excellent resistance to H2SO4.