Several types of vanadium metal alloys are produced industrially for a number of different applications. Vanadium is most commonly alloyed with iron in various steel alloys, but it is also alloyed with materials such as titanium and gallium. Vanadium metal is used for its high strength and its ability to maintain that strength at high temperatures. Some vanadium alloys also have other useful properties, such as superconductivity and corrosion resistance.
Vanadium is a silver-gray metal. It is element 23 on the periodic table, and its most common form has an atomic weight of 50.9. It is soft and ductile, with a melting point of 3470°F (1910°C, or 2183° K). It is never found in a pure state in nature and is extracted for human use from minerals such as vanadinite, magnetite, and carotite, usually in the form of vanadium oxide (V205), also called vanadium pentoxide. It has two natural isotopes, with the vast majority of vanadium in the form of vanadium-51, which is stable, and a small percentage in the form of the radioactive isotope vanadium-50.
An iron-vanadium alloy made from at least 35 percent vanadium is called ferrovanadium. Ferrovanadium is used in the production of steels made from vanadium and iron, the primary use for vanadium metal. These steel alloys also sometimes include other alloying metals, such as nickel, aluminum, and chromium.
The vanadium gives the steel greater strength and better performance at high temperatures. High-carbon vanadium steels have very small amounts of vanadium, about 0.15 percent to 0.25 percent. High-speed tool steels can have much higher vanadium metal content, as much as 14.5 percent. Steel alloys containing vanadium are often used in applications that require strength and resistance to heat, such as cutting tools and engine parts.
Vanadium is also used in titanium alloys, usually in combination with the metal aluminum. These alloys, which are usually around 4 percent vanadium, are costly but can have excellent strength and toughness that is maintained at very high temperatures. They are also light and resistant to corrosion. Titanium alloys containing vanadium are commonly used for aerospace and military applications that require high heat resistance, such as in engines and turbines, and in the engines of high-performance automobiles. They also have high biocompatibility, meaning that they do not have toxic effects on living tissue or cause damaging immune system responses, and so are often used in implanted medical devices.
Vanadium alloyed with gallium is a superconducting alloy used in superconducting magnets. A superconductor is a material that conducts electricity with no electrical resistance at very low temperatures. Vanadium-gallium becomes superconductive at a temperature of only 14.2° Kelvin above absolute zero (-434.1°F, or -258.9°C). Vanadium-gallium alloys can also contain small amounts of other elements such as niobium, tin, or platinum.