Nickel is a silvery-white metal valued for corrosion and heat resistance, playing a key role across three major fields: steel, batteries and surface engineering. Its largest use is in stainless steel: a substantial share of primary nickel goes into austenitic stainless steel, where the chromium-nickel alloy forms a dense passivating film in air, so that kitchenware, chemical equipment, building façades and medical instruments remain rust-free for decades. The battery industry is nickel's fastest-growing segment: nickel in NiMH and NMC lithium-ion batteries sharply raises energy density, and the rollout of electric vehicles and grid storage stations has directly pulled nickel demand. Electrodeposited nickel coatings are attractive, wear-resistant and corrosion-protective, widely used to decorate and protect hardware, automotive components and electronic connectors. In alloying, nickel-based superalloys serve the hot-section components of aero engines and gas turbines, while specialty materials such as Monel and Inconel underpin chemical, marine and nuclear power equipment.
Nickel sulfide (NiS) occurs mainly in nickel sulfide ores such as pentlandite and millerite; it is an intermediate of pyrometallurgical nickel production, obtained as nickel matte through matte smelting and then further converted and electrorefined. Nickel(II) oxide (NiO), a green powder, is a feedstock for nickel salts, nickel catalysts and magnetic materials, and is also used as a colorant in glass and ceramics. Nickel sulfate (NiSO4) is the core chemical for nickel electroplating baths and battery cathode precursors: cobalt sulfate, manganese sulfate and nickel sulfate are mixed in the right proportions and co-precipitated to make NMC precursors that determine the battery material's composition. Nickel(II) hydroxide (Ni(OH)2) is the positive active material in NiMH and NiCd batteries; high-density spherical nickel hydroxide in foam electrodes is still used in hybrid-vehicle batteries and backup power supplies.
