Tantalum
Atomic number: 34
Density: 16.68g / cm^3
Melting point: 2996 ° C
Boiling point: ~ 5694 ° C

Areas of application for tantalum and tantalum alloys
Most of the tantalum is used for very small capacitors with high capacitance. In 2007 this was 60%. These tantalum electrolytic capacitors are used everywhere in modern microelectronics, for example for mobile phones and in automotive engineering. The effect is based on the tantalum oxide layer, which is stable and securely insulating, even in a very thin version, on the surface of the wound tantalum foil. The thinner the layer between the electrodes, the higher the capacity with the same film area; tantalum oxide also has extremely high perittivity, which also increases capacity.

Because tantalum is non-toxic and does not react with body tissues or fluids, elemental tantalum is used for medical implants and instruments. For example, bone nails, prosthesis, brackets and jaw screws are made from tantalum. In addition, it is an X-ray contrast medium that is used little due to the high cost.

Tantalum is used in the chemical industry because of its durability. It serves as a lining for reaction vessels and is used for heat exchangers and pumps. Usually, pure tantalum is not used for this purpose, but alloys containing 2.5 - 10% tungsten. These are more stable and more resistant than pure tantalum. At the same time, the desired ductility is maintained. Other uses are laboratory equipment, spinnerets and the cathodes of electron tubes. Here tantalum benefits from the fact that it is able to absorb up to 740 parts by volume of gases at 800 ° C, which ensures a high vacuum in the tubes.

Superalloys used in the construction of turbines and aircraft engines contain up to 9% tantalum. The addition of 3-4% tantalum to a nickel superalloy increases the strength of the material at high temperatures.

Special properties
Tantalum has a very high melting point of 2996 ° C. Tantalum is also characterized by good ductility with great hardness. The most important tantalum feature is its excellent corrosion resistance. Most tantalum properties are closely related to the purity of the tantalum metal. In addition to the use in capacitors, in tantalum alloys for hard metal and tantalum-containing superalloys, tantalum is used for the production of hard, heat-resistant and extremely corrosion-resistant instruments and devices (including tantalum sheets, tantalum tubes, tantalum wires, etc.). Here, tantalum partially replaces the considerably more expensive platinum.
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