Tantalum is a metal element with atomic number 73 and chemical symbol TA. The elemental substance corresponding to the element is steel gray metal, which has extremely high corrosion resistance. It does not react with hydrochloric acid, concentrated nitric acid and “aqua regia” under both cold and hot conditions.
Tantalum mainly exists in tantalite and coexists with niobium. The hardness of tantalum is moderate , which is full of ductility, and it can be pulled into fine wire to make thin foil. Its coefficient of thermal expansion is very small. Tantalum has excellent chemical properties and high corrosion resistance. It can be used to make evaporating vessels, etc., and can also be used as electrodes, rectifiers and electrolytic capacitors of electronic tubes. Medically, it is used to make thin slices or thin threads to repair damaged tissues. Although tantalum has strong corrosion resistance, its corrosion resistance is due to the formation of stable tantalum pentoxide (ta‹o ₅) protective film on the surface.