An important use of niobium is the formation of alloys. It enhances the strength of iron and steel and makes them more heat resistant. At high temperatures, pure steel is subject to a phenomenon called "creep," which means that the molecules gradually slip from their proper place as a result of forces acting upon them. Pure steel is also subject to a phenomenon called "fatigue," which means that they tend to wear out when stress is repeatedly applied to them. The addition of niobium gives steel a resistance to both creep and fatigue. In addition, workmen find that steel-niobium alloys are more pliable than pure steel. Besides steel, niobium also forms alloys with such metals as tin, nickel, cobalt, titanium and zirconium.
Niobium alloys serve as materials in the construction of planes and rockets. They withstand the intense heat generated by jet engines. Some rocket thruster nozzles have used alloys in which niobium is the principal metal, with only a little hafnium and titanium mixed in. The Gemini program also used a copious amount of niobium alloys in the bodies of its rockets. Niobium alloys are also sufficiently refractory materials for nuclear reactors. It helps control nuclear reactions by absorbing neutrons.
At normal temperatures even the best conductors offer plenty of resistance to current flow. However, at very low temperatures, some materials become superconductors and offer no resistance to electrical current. For example, mercury becomes a superconductor at a temperature of 4.2 K. Other materials become superconductors at somewhat higher temperatures. One of the best superconductors is an alloy of niobium and tin. While some superconductors lose their superconductivity when places in a magnetic field, a niobium-zirconium alloy does not. Important applications of superconductor technology are their use in particle accelerators and magnetic resonance imaging, a process that has largely displaced X-rays as a diagnostic medical tool.
Metals occasionally cause allergic reactions when in contact with the body for a long time, but niobium is less likely to cause problems than many other metals. For this reason, niobium or niobium alloys serve as a material for such objects as pacemakers and especially jewelry. Above all, metal objects inserted into pierced ears or noses often use niobium alloys.
Niobium serves as a component in such novelties as commemorative coins and skateboards. Niobium diselenide is a lubricant that operates effectively at high temperatures. Corrective glasses, capacitors, U-tubes and welding equipment also use niobium as a component. It formerly served as material for light bulb filaments.