Tantalum: Properties, Uses, and Characteristics

Tantalum

Tantalum

Tantalum, a bluish-gray metallic chemical element. When polished, tantalum is silvery-white, resembling platinum. Tantalum is a good conductor of heat and electricity. It is ductile (capable of being drawn into a wire) and malleable (capable of being hammered or rolled into a thin sheet), and can combine with many other metals to form alloys. Tantalum has a very high melting point, one that is exceeded only by tungsten and a few other elements. It is chemically stable against all acids except boiling sulfuric acid and those containing fluorine. Alkalies react slowly with tantalum. At high temperatures, tantalum is capable of absorbing hydrogen, oxygen, and other gases.

Uses

A large percentage of the tantalum produced is used by the electronics industry in the manufacture of capacitors. Tantalum's strength and high melting point make it useful in the construction of vacuum furnaces. It is also used to make laboratory weights and crucibles, as well as containers for acids and for plutonium in nuclear reactors.

Because tantalum does not react with body acids and is not toxic to body tissues, it is used for the surgical repair of broken bones and for suture wire. Tantalum is alloyed with steel to make surgical and dental instruments. Tantalum carbide, an extremely hard alloy, is used separately or combined with other carbides to make cutting tools, forging dies, jet-engine turbine blades, and coatings for rocket nozzles.

Occurrence and Production

Tantalum was discovered by the Swedish chemist Anders G. Ekeberg in 1802. It is widely distributed in the earth's crust, but deposits are small. Tantalum is nearly always found in combination with niobium and other chemical elements in the ores tantalite and columbite, and with calcium in the ore microlite. Tantalum materials are mined by both open-pit and underground methods. The leading producers usually are Australia and Brazil. Tantalum is also recovered from slags produced at tin smelters throughout the world.

Symbol: Ta. Atomic number: 73. Atomic weight: 180.9479. Specific gravity: 16.6. Melting point: 5,425 F. (2,996 C.). Boiling point: 9,797 F. (5,425 C.). Tantalum has two stable isotopes, Ta-180 and Ta-181. It belongs to Group VB of the Periodic Table and can have a valence of +2, +3, or +5.