Appearance and Characteristics
Harmful effects:
Some niobium compounds are highly toxic.
Characteristics:
Niobium is a shiny, white, ductile metal. In air an oxide layer forms whose color depends on its thickness. Shades of blue, green and yellow are typical.
Niobium resists corrosion due to the oxide film. The metal starts to oxidize rapidly in air at 200 oC.
Niobium’s chemical properties are very similar to those of tantalum.
Niobium is one of the five major refractory metals (metals with very high resistance to heat and wear). The other refractory metals are tungsten, molybdenum, tantalum and rhenium.
Uses of Niobium
Niobium is used with iron and other elements in stainless steel alloys and also in alloys with a variety of nonferrous metals, such as zirconium.
Niobium alloys are strong and are often used in pipeline construction.
The metal is used in superalloys for jet engines and heat resistant equipment.
Niobium is also used for jewelry. At cryogenic temperatures, niobium is a superconductor.