Using Metal Alloys to Prevent Corrosion
Nickel-based metal alloys have excellent corrosion resistance properties, so they’re the materials of choice for the construction of applications for many different industries that are used in aqueous environments – such as pumps, valves and piping systems.
NeoNickel’s technical staff will be delighted to supplement the following brief guide to nickel and its alloying elements with more specific information. Please get in touch to discuss specific alloy properties and to share in our experience of alloy applications and their service and performance, so we can help supply your best solution.
Pure nickel is very corrosion resistant, especially to a variety of reducing chemicals. Alloying it with chromium gives resistance to oxidation – this leads to a broad variety of alloys with optimal corrosion resistance in both reducing and oxidising environments.
Alloys based on nickel can tolerate more additional alloys than stainless steel and other iron-based materials while maintaining good stability. This flexibility has led to the development of a variety of nickel-based alloys with multiple additional alloys designed to be resistant to a host of different corrosive environments.
Many alloying elements can be joined with nickel to resist corrosion in a variety of environments and supplied by NeoNickel . The exact metal alloy that’s right for you depends on your circumstances and there are many potential options.
Nickel gives alloys metallurgical stability. Alloys have more thermal stability and weld better. Resistance to reducing acids and caustics is heightened. Resistance to stress corrosion cracking – specially in chlorides and caustics – is increased.
Chromium – Resistance to oxidising corrosives and to high temperature oxidisation and sulfidation is improved. Resistance to pitting and crevice corrosion is boosted.
Molybdenum – Resistance to reducing acids, to pitting and crevice corrosion in environments containing aqueous chloride is improved. It increases high temperature strength.
Iron – Resistance to high-temperature carburising environments is improved and helps control thermal expansion. It reduces alloy costs.
Aluminium – Encourages age hardening. Resistance to oxidation and heightened temperatures is improved.
Copper – Resistance to reducing acids – notably non-aerated sulphuric and hydrofluoric – and to salts is improved. Added to nickel-chromium-molybdenum-iron alloys it boosts resistance to hydrochloric, phosphoric and sulphuric acids.
Niobium (formerly known as Columbium) – Combines with carbon and vulnerability to intergranular corrosion caused by chromium carbide precipitation that stems from heat treatments is reduced. It increases high temperature strength. Resistance to pitting and crevice corrosion is improved.
Tungsten – Resistance to reducing acids and localised corrosion is improved. Weldability and strength are both boosted.
Nitrogen – Metallurgical stability is heightened. It increases high temperature strength. Resistance to carburisation and sulfidation is improved.
Many of these elements can be alloyed with nickel in different combinations. So a very broad range of corrosion resistant alloys is available to suit a wide variety of environments. Because of their metallurgical stability, these alloys can be fabricated and thermally processed without risk of harmful consequences. Many alloys with a high nickel content can also be strengthened by hardening processes, precipitation hardening, dispersion strengthened powder metallurgy and carbide precipitations.
The technical staff at NeoNickel will be happy to discuss your specific metal alloy requirements in more detail, contact us today for more information!