Nickel (Ni), atomic number 28, is a silvery-white transition metal with a slight golden luster. It is highly valued across diverse industries because of a unique combination of physical and chemical properties. Nickel is notably malleable and ductile, meaning it can be easily shaped and drawn into thin wires.
Its natural resistance to corrosion and oxidation stems from a thin, passive oxide layer on its surface, making it highly durable. Nickel is also one of only four elements that are ferromagnetic at or near room temperature, a property indispensable in certain high-tech applications. These qualities make nickel a ubiquitous material in modern manufacturing.
Nickel in Everyday Consumer Products
Nickel’s combination of durability, aesthetic appeal, and relatively low cost makes it a popular component in numerous items the average person interacts with daily. A prime example is coinage, where nickel is alloyed with copper to create a durable, silvery metal. United States five-cent coins, often called “nickels,” are 75% copper and 25% nickel, providing high resistance to wear.
Beyond the five-cent piece, the outer layer of other US denominations, such as dimes and quarters, is a cupronickel cladding over a pure copper core. Nickel is also widely used in various accessories and household items, including zippers, metal buttons, belt buckles, spectacle frames, and plumbing fixtures like faucets. These items often rely on nickel plating to provide a bright, corrosion-resistant finish that prevents the underlying base metal from tarnishing.
In the jewelry industry, nickel is used to create white gold alloys, contributing to the metal’s hardness and its characteristic white color. Costume jewelry frequently uses nickel alloys or nickel plating due to their inexpensive nature and bright finish. However, the nickel used in these consumer goods is the most common cause of allergic contact dermatitis in the industrialized world.
This irritation occurs when nickel plating wears down, allowing small amounts of the metal to leach out, especially when dissolved by sweat. Regulatory bodies in many regions now impose strict limits on the rate at which nickel can be released from products intended for prolonged skin contact. For example, items like earrings must meet a much lower nickel release rate than a typical household door handle to mitigate the risk of allergic reaction.
Structural and High-Performance Alloys
Nickel is a fundamental alloying element in materials requiring bulk strength, heat resistance, and long-term corrosion performance. The most widespread use of nickel in this category is in the production of stainless steel, a material integral to architecture, kitchenware, and medical devices. Specifically, nickel stabilizes the austenitic crystal structure in steels like the common 304 and 316 grades.
Austenitic stainless steels typically contain between 8% and 14% nickel, which imparts significant ductility and makes the steel non-magnetic. This nickel content provides exceptional resistance to corrosion, particularly against acids and chloride environments, making it suitable for food preparation equipment and surgical instruments. Without nickel, these common stainless steel types would be far more susceptible to rust and cracking under stress.
For conditions involving extreme temperatures and high mechanical stress, nickel is the primary component in highly engineered superalloys. These nickel-based superalloys can contain over 50% nickel, combined with elements like chromium, cobalt, and molybdenum. The resulting materials exhibit superior strength and resistance to creep and oxidation at temperatures exceeding 1,000°C.
This high-performance characteristic makes nickel superalloys indispensable in aerospace and power generation. They are used to manufacture turbine blades and combustion components in jet engines and industrial gas turbines, where other metals would quickly fail. Specialized piping and valves in chemical processing plants also rely on high-nickel alloys like Inconel and Hastelloy, which can withstand aggressive chemical attack over long operating periods.
Functional Roles in Energy and Chemical Processing
In addition to structural and decorative uses, nickel plays a distinct functional role in modern technology, particularly in energy storage and chemical manufacturing, leveraging its electrochemical properties. For decades, nickel has been a component in rechargeable batteries, notably in Nickel-Metal Hydride (NiMH) batteries used in hybrid electric vehicles and some consumer electronics. This application utilizes nickel’s ability to transfer and store electrons efficiently.
Today, nickel’s role is even more pronounced in the cathode materials of advanced lithium-ion batteries that power electric vehicles (EVs) and portable electronics. Chemistries such as Nickel-Manganese-Cobalt (NMC) and Nickel-Cobalt-Aluminum (NCA) are increasingly nickel-rich, with the metal accounting for a growing percentage of the cathode composition, such as in NMC 811 formulations. The higher nickel content directly increases the battery’s energy density, allowing for longer driving ranges in EVs and extended life in mobile devices.
Nickel compounds are also widely employed as catalysts, substances that accelerate chemical reactions without being consumed. In the food industry, a finely divided form of nickel, known as Raney nickel, is used to facilitate the hydrogenation of vegetable oils. This process converts liquid oils into solid or semi-solid fats, a step used in the production of margarine and certain shortenings.
Nickel catalysts are similarly utilized in the petrochemical industry to produce synthetic fibers and various polymers. In these applications, nickel’s chemical reactivity profile makes it highly effective at promoting specific molecular rearrangements and additions.