Q: What is Tungsten?
A:Tungsten is a metal element, the element symbol is W, it has high hardness, high melting point, and is not corroded by air at room temperature; its main purpose is to manufacture filaments, high-speed cutting alloy steel, super-hard molds, and also used in optical instruments and chemical instruments. China is the world’s largest tungsten storage country.
The atomic number of tungsten is 74, the relative atomic mass is 183.85, the atomic radius is 137 picometers, and the density is 19.35 grams per cubic centimeter. It belongs to the VIB group of the sixth period (the second longest period) of the periodic table. Tungsten is mainly a hexavalent cation in nature, and its ion radius is 0.68×10-10m. After smelting, tungsten is a silver-white shiny metal with extremely high melting point, high hardness, low vapor pressure, low evaporation rate, and relatively stable chemical properties.
The tungsten-copper alloy (10%-40% copper) and tungsten-silver alloy manufactured by powder metallurgy have the good electrical and thermal conductivity of copper and silver and the wear resistance of tungsten. Therefore, it becomes a very effective contact material for manufacturing working parts such as knife switches, circuit breakers, and spot welding electrodes. The composition is 90%-95% tungsten, 1%-6% nickel, 1%-4% copper high specific gravity alloy, and the alloy with iron instead of copper (-5%), used to make top The rotor of the instrument, the airplane, the counterweight that controls the rudder, the radiation shield and the feed basket of the radioisotope, etc.
Electric vacuum lighting materials: Tungsten is used in electronic tube production, radio electronics and X-ray technology with tungsten wire, tungsten ribbon and various forged components. Tungsten is the best material for white woven filament and spiral filament. The high working temperature (2200-2500℃) guarantees high luminous efficiency, while the small evaporation speed guarantees the long life of the filament. Tungsten wire is used to manufacture direct heating cathodes and grids of electronic oscillating tubes, cathodes of high-voltage rectifiers and indirect cathode heaters in various electronic instruments. Tungsten is used as the counter cathode and cathode of X-ray tubes and gas discharge tubes, as well as the contacts of radio equipment and the electrodes of atomic hydrogen welding torches. Tungsten wires and tungsten rods are used as heaters for high-temperature furnaces (3000°C). Tungsten heaters work in hydrogen gas, inert gas or vacuum.
Tungsten compounds: Sodium tungstate is used in the production of certain types of paints and pigments, as well as in the textile industry for fabric weighting and mixing with ammonium sulfate and ammonium phosphate to make fire-resistant fabrics and waterproof fabrics. Also used in the manufacture of metal tungsten, tungstic acid and tungstate, as well as dyes, pigments, inks, electroplating, etc. Also used as a catalyst. Tungstic acid is used as a mordant and dye in the textile industry and as a catalyst for the production of high-octane gasoline in the chemical industry. Tungsten disulfide is used as a solid lubricant and catalyst in organic synthesis, such as the preparation of synthetic gasoline. When tungsten ore is processed, tungsten trioxide can be obtained, and then tungsten trioxide is reduced by hydrogen to prepare tungsten powder, which is widely used as raw material for tungsten materials and tungsten metallurgical materials.
In aviation and rocket technology, as well as other sectors that require high thermal strength of machine parts, engines and some instruments, tungsten and other alloys for melting metals (tantalum, niobium, molybdenum, rhenium) are used as heat-strength materials.
What is Tungsten?
Q: What is Tungsten?