Tantalum

Tantalum is a gray, dense (S.G. 16.65 g/cc), hard metal, a member of the transition group of elements (Group Vb). It is rare, averaging 2 ppm in the earth’s crust and its principal source is pegmatites. It also occurs in granitic greisen zones and is recovered from placers along with cassiterite (tin). Tin slags are an important source of tantalum. It occurs in a number of oxide minerals usually containing varying amounts of niobium, manganese, iron and tin. Most common is the columbotantalite series, and microlite.

PROPERTIES AND APPLICATIONS OF TANTALUM

Tantalum is remarkable for its unsurpassed performance in the diverse end uses that it serves. Only tungsten, rhenium and osmium have higher melting points (Ta at 3017 C), its tensile strength at 130,000 psi (91kg/mm2) is about double that of high strength alloy steels, the carbide is the hardest of the metal carbides, the metal is virtually untouched by most acids and even by fused alkalis, and Ta powder has the highest capacitance per gram of any material.

• Electronics: About 2/3 of all tantalum used is for electronic components, chiefly capacitors which are fundamental to all electronic products. Its amenability to miniaturization and its durability are unmatched
• Metallurgy: High strength, high temperature alloys find service in jet engines and other high temperature applications. Tantalum metal is used directly to coat equipment that functions in highly corrosive and high temperature environments such as chemical processing plants, nuclear plants, missiles, etc.
• Wear resistant products: The super hardness of tantalum carbide is used for cutting tools, teeth for construction and mining equipment, drill bits, pavement shavers etc. A new product, tantalum carbide graphite composite may be the hardest material made by man. It has a melting temperature of 3738 C.
• Glass: Tantalum oxide added to glass greatly increases refractive index making possible lighter spectacle, camera and other lenses.
• Medical: The metals virtual immunity to attack by chemicals and its non allergenic character find use in surgical appliances and implants.
• Other: Gettering ability (absorption of gasses) in vacuum tubes and furnaces, catalyst for synthesis of butadiene (rubber industry) and many other uses