In order to form compounds and alloys that work well for different applications, nickel suppliers frequently combine nickel with other elements, such as aluminum, titanium, and chromium. A few common alloys include nickel 200 and stainless steel. Nickel 200, which is 99.6% nickel, but alloyed with a number of different elements, including copper, iron, carbon, silicon, sulfur, magnesium, and more, is typically stocked by nickel suppliers in the form of nickel bars, nickel rods, nickel plate, nickel sheet, and, occasionally, nickel tubing.
Stainless steel, which is mostly iron, as well as 18% chromium and 8% nickel, is the most commonly used nickel alloy element of all.
Other metal alloys made with nickel include Kovar, Invar, Monel, Nichrome, Inconel, and the various Hastelloys. Of these, the three most frequently used are Kovar, Monel, and Inconel.
Kovar is a ferrous alloy, primarily made up of nickel and cobalt, accompanied by trace amounts of copper, manganese, and silicon. The term “Kovar” can also refer to a large group of nickel alloys that are compatible with the thermal expansion characteristics of borosilicate glass. Such alloys are frequently used as electroplated conductors of system parts like x-ray tubes and vacuum tubes.
Similarly, Monel is the general name of a group of nickel alloys that are approximately 67% nickel and otherwise composed of iron, copper, and inconsequential amounts of other elements. Monel has incredible corrosion resistance, and so is used to make marine application components, such as seawater valves, pump shafts, and trolling wire.
Though it also refers to a family of alloys, Inconel itself is a superalloy, or a high-performance alloy, that displays uncommonly high heat resistance. This alloy is made primarily of nickel, molybdenum, niobium, and chromium, along with minute amounts of aluminum, boron, carbon, cobalt, copper, manganese, phosphorus, silicon, sulfur, and titanium. Alloys in the Inconel family are well-suited to extreme environments, where they are commonly found as seals, combustors, gas turbine blades, nuclear pressurized water reactors, electric submersible well pump shafts, pressure valves, and more.
Before nickel suppliers can refine and shape the element into usable parts and products, nickel must be extracted. Found deep within the earth, nickel is mostly mined in Russia, which carries 40% of the market, and Canada, which produces 30% of the world’s supply. Countries that produce the remaining percentages include Australia, Cuba, France, Indonesia, and New Caledonia.
Nickel ore deposits are found in two main forms: laterites and magmatic sulfide deposits. The former is composed primarily of garnierite and nickeliferous limonite and the latter is mostly made up of an ore mineral called pentlandite. To glean nickel from these deposits, refiners put them through a process called extractive metallurgy, during which the raw material is extracted and purified into a more refined form.
The two most common methods of metallurgy include pyrometallurgical extraction and hydrometallurgy. One part of extractive metallurgy is the roasting and reduction stage. Using conventional methods, roasting and reduction produces refined nickel that is more than 75% pure. For even greater purity, however, nickel suppliers can continue to process the nickel. One common process is the Mond process, during which nickel oxides are converted into nickel that is 99% pure. This process uses carbon monoxide, and so nickel it refines is called carbonyl nickel.
Once refined, nickel suppliers may put the nickel through any number of fabrication processes to achieve their ends. Most commonly, nickel is used in the chemical reduction process known as electroless nickel plating. The goal of this process is to deposit metal nickel onto a surface without using electrical energy.
To achieve this, the nickel is placed in an aqueous solution that contains a chemical reducing agent, wherein a catalytic reduction takes place, causing nickel ions to deposit on the surface of the product. Electroless nickel plating produces nickel plating that is very uniform in thickness, shape, and size.
Quite commonly, nickel is also shaped in a cold drawing process. During cold drawing, without the introduction of heat, nickel wire or tube is forced through a series of smaller and smaller dies, in order to reduce its diameter. Rarely, nickel is melted and forced through a die, or extruded, to produce rods, sheets, bars, and tubing.