Tungsten :Technical Information


Incandescent lamps: Tungsten is used as a filament because of its non sag characteristics necessary for this application.
High temperature: In high temperature furnaces the heating element are made out of tungsten tungsten by virtue of its high melting point.
Electrical Contacts: Tungsten is pure form or alloyed with copper and silver is used for electrical contact material.Because of its high melting point ,its resistance to wear and spark erosion and its low electrical resistivity.
Welding Electrodes: Tungsten is used for heater elements and supports in high power electron tube because of the good mechanical properties of tungsten at high temperatures.Thoriated tungsten is used to ti increase the electron emissivity at high temperature.
Electron Tubes: Tungsten is used for heater element and support in high power electron tubes because of the good mechanical properties of tungsten of high temperature. Thoriated tungsten is used to increase the electron emissivity at high temperature.
X-ray Tubes: Because of high atomic number and high melting point ,tungsten is an ideal material for anodes in X-ray tubes.
Vacuum Deposition: Tungsten wires and boats are used for vacuum evaporation and deposition of several material such aluminum,gold,nickel,platinum.etc.

Physical Property of Tungsten:
Atomic Number: 74
Atomic Weight: 183.8
Density: 19.3 gm/cc
Melting Point: 3400°c
Boiling Point: 5555°C
Specific Heat:

Temperature: ( Cal/g/ C° )
20° C: 0.034

Electrical Resistivity:

Temperature: ( Micro-ohm / cm ²/ cm )
20° C: 5.5
Mechanical Property:
Hardness ( 10 Kg. load ): 380 – 490 VPN
Modulus of elasticity at 20° C: 40,600 Kg / mm²
Chemical Property:

Air: Tungsten oxides on heating in air above 400° C
Hydrogen: No reaction at all
Nitrogen: Reaction starts after 2400° C
Corrosion Resistance: Good Resistance