Physical Properties of Tantalum

Chemical symbol Ta, steel gray metal, belongs to VB group in the periodic table, atomic number 73, atomic weight 180.9479, body-centered cubic crystal, common valence is +5. The hardness of tantalum is relatively low and is related to the oxygen content. For ordinary pure tantalum, the Vickers hardness in the annealed state is only 140HV. Its melting point is as high as 2995°C, ranking fifth among the elements after carbon, tungsten, rhenium and osmium. Tantalum is ductile and can be drawn into filaments to make thin foils. Its thermal expansion coefficient is small. It only swells by 6.6 millionths of a degree per degree Celsius. In addition, its toughness is very strong, even better than copper.