Due to its unique properties, tungsten foil is widely used. It is used in many areas of life, from medicine to mechanical engineering, nuclear power.
The properties
Despite the small thickness (only 0.03-0.09 mm), tungsten foil has amazing characteristics:
- Heat resistance and heat resistance. Long service life even at temperatures up to 2500 degrees.
- High compression ratio (tensile).
- The great importance of electrical resistance.
- Very low coefficient of thermal expansion.
- High value of resistance to thermal creep.
- High value of the electronic emission indicator.
- It is not subject to corrosion.
- Resistant to chemicals (acids, alkalis, aqua regia).
- Allowed to use in aggressive environments with high temperature and high loads.
Along with many advantages, the material has its drawbacks:
- Pure tungsten is difficult to obtain, since it is quite rare.
- At low temperatures, the material becomes brittle.
- Tungsten is a refractory and capricious raw material that is difficult to work with.
- Production is possible only with the strongest heating of raw materials.
Due to refractoriness, rarity of raw materials, difficulties during its processing, the price of finished products is high.
Production
Pure metal tungsten foil is produced. Sheets are obtained by pressing prepared dies. After that, the metal is heated and forged at a temperature of 1500-1700 degrees.
To protect against oxidation, rolling of still hot metal at high speed is used. When the sheet thickness reaches 0.6 mm, the rolling speed is reduced. The thinnest sheets are obtained by cold rolling. To make the surface of the foil smooth, run-in is used.
A hot sodium solution is used to remove oxidation stains. Next, the sheet is calcined in the presence of hydrogen at a temperature of 1000 degrees.
Application area
Apply tungsten foil (VA 0.05 mm including) in many areas. The main ones are:
Due to its unique properties, tungsten foil is used as heat shields; elements of heating pads and heat exchange equipment are made from it.