Nickel plays a key role in daily life; it facilitates food preparation, is used to create mobile phones and medical equipment, and enables power generation, transportation and construction among other trades. Nickel is classified as an alloy, along with iron and chromium. These elements are considered stainless steels, and are used primarily in industrial and commercial settings, as they withstand high pressures, heat and use.
Nickel is also used in many areas of electronics and specialty engineering. It is used in its pure form as well as alloy form; most nickel extracted is used to create alloys, most of which make stainless steel. Nickel is used to create hard-wearing decorative and engineering coatings, commonly called nickel plates or electroless nickel coats. Nickel is added to rechargeable battery systems in cars and electronics, as well as power tools, transportation equipment and emergency power supplies. Nickel is a primary ingredient in many catalysts and converters; when added to these devices, nickel makes chemical reactions more efficient. Nickel is also used to create plumbing and piping for residential and commercial structures, and helps form the interior wall of engines in trains, planes and some cars. Nickel is also used as currency, and it even has nutritional value; it is consumed in trivial amounts by living organisms.