(Chemical symbol: Ta). A ductile, gray metallic element. It is known for its resistance to a wide variety of acids, alcohols, chlorides, sulfates, and other chemicals. Tantalum is used as an alloy in metals, and is also used in electrical capacitors and high-temperature furnace components. Atomic number, 73; atomic weight, 181; melting point, 2910°C (5270°F).

Although tantalum has an extremely high melting point, and readily combines with all but the inert gases, this reactive metal will produce strong, ductile welds when welded by the gas tungsten arc welding (GTAW) process. Welding is preferably done in a vacuum chamber. The thermal conductivity of tantalum is somewhat lower than that of steel; the thermal coefficient of expansion is about the same as steel.

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