As a typical tungsten product, tungsten wire is a fine filament made by forging and drawing tungsten rods, known in English as tungsten wire, with a tungsten content generally exceeding 99.95%. However, due to the high hardness and brittleness of metallic tungsten, which makes processing difficult, small amounts of potassium oxide, silicon oxide, and aluminum oxide are often added during production. The resulting modified tungsten wire is commonly referred to as doped tungsten wire, 218 tungsten wire, or non-sagging tungsten wire, offering superior overall performance compared to pure tungsten wire.
In terms of physicochemical properties, tungsten wire is characterized by a high melting point, high density, high strength, high electrical resistivity, low vapor pressure, slow evaporation rate, high-temperature resistance, wear resistance, impact resistance, and acid-alkali resistance. Notably, it can be categorized into black tungsten wire and white tungsten wire based on color; into straight twisted fine wire, twisted fine wire, and spiral fine wire based on shape; and into coarse tungsten wire and fine tungsten wire based on size.
Regarding production processes, the preparation of doped tungsten wire involves: first mixing ammonium paratungstate, potassium silicate, aluminum nitrate, potassium hydroxide, and hydrochloric acid solution; then spray-drying the mixture, reducing the resulting powder with hydrogen to produce doped tungsten powder; and finally processing it through molding, vertical melting, rotary forging, and drawing to obtain the desired product.
In terms of applications, tungsten wire is used in lighting, semiconductor, and photovoltaic fields. In lighting, it primarily serves as the filament for incandescent lamps and halogen tungsten lamps. Note: The filament is shaped into a spiral primarily to maximize its length while keeping resistance low, thereby enhancing the bulb’s brightness and lifespan.
