Nickel

Because of nickel's slow rate of oxidation at room temperature, it is considered corrosion-resistant. Historically on Earth and other worlds this has led to its use for plating metals such as iron and brass, to its use for chemical apparatus, and its use in certain alloys that will retain a high silvery polish, such as German silver on Earth or ancient Norshk hunting harpoons. Nickel production is still used for corrosion-resistant pure-nickel plating by moderately advanced societies. Nickel was once a common component of many Earth coins, but has largely been replaced by cheaper iron for this purpose, especially since the metal has proven to be a skin allergen for some humans. Nickel is one of the four elements that are ferromagnetic around room temperature. Alnico permanent magnets based partly on nickel are of intermediate strength between iron-based permanent magnets and rare-earth magnets. The metal is chiefly valuable in the modern world for the alloys it forms, about 60% of Earths nickel production is used in nickel-steels (particularly stainless steel). Other common alloys, as well as some new superalloys, make up most of the remainder of human nickel use, with chemical uses for nickel compounds consuming less than 3% of production. As a compound, nickel has a number of niche chemical manufacturing uses, such as a catalyst for hydrogenation. Enzymes of some microorganisms and plants contain nickel as an active center, which makes the metal an essential nutrient for them.