As a typical tungsten product, tungsten wire is a fine wire made of tungsten bars after forging and drawing. the tungsten content is generally more than 99.95%. However, tungsten is hard and brittle, and difficult to process, so appropriate amounts of potassium oxide, silicon oxide, and alumina are often added to the tungsten filament production process. The modified tungsten filament can be called doped tungsten filament, 218 tungsten filament, or no pending tungsten filament. Its comprehensive performance is better than pure tungsten wire.
In terms of physical and chemical properties, the tungsten product is characterized by high melting point, high density, high strength, high resistivity, low vapor pressure, slow evaporation rate, high-temperature resistance, abrasion resistance, impact resistance, acid-base resistance, etc. It is important to note that, depending on the color, it can be divided into white and Black tungsten wire. Depending on the shape, they can be divided into twist straight filaments, twisting filaments, and spiral filaments. Depending on the size, it can be divided into coarse and fine tungsten wires.
In terms of production technology, the preparation steps of doped tungsten wire are as follows: firstly, ammonium metatungstate, potassium silicate, aluminum nitrate, potassium hydroxide, and hydrochloric acid solution are mixed; the mixed solution was then sprayed and dried, and the dried powder was reduced by hydrogen to make the doped tungsten powder. finally, after pressing, vertical melting, rotary forging, drawing, and other operations, the required products can be obtained.
In terms of application, tungsten wire can be used in lighting, semiconductor, photovoltaic and other fields. In the field of lighting, it is mainly used as the filament of electric light source such as incandescent lamp and tungsten halogen lamp.
Note: the main reason why the filament is made into a spiral shape is to prolong its length as much as possible under the condition of ensuring low filament resistance, so as to improve the brightness and service life of the bulb.
