Tungsten can only be used for light bulbs, right?Wrong!It is an important part of modern high-tech new materials!
Tungsten is the refractory metal with the highest melting point.Generally, metals with melting point higher than 1650℃ and certain reserves and metals with melting point higher than zirconium melting point (1852℃) are called refractory metals.
Tungsten is a rare high melting point metal, and can improve the high temperature hardness of steel, belongs to the periodic table 6 cycles Ⅵ group B (2) for a long period of time.Tungsten is a silver-white metal that looks like steel.Tungsten has a high melting point, low vapor pressure, and low evaporation rate.The chemical properties of tungsten is very stable, normal temperature with air and water reaction, not heating, any concentration of hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid and water do not have any effect on tungsten, when the temperature rises to 80° -100 °C, the above acids, in addition to hydrofluoric acid, other acids have a weak effect on tungsten.
Tungsten dissolves quickly in a mixture of hydrofluoric acid and concentrated nitric acid at room temperature, but does not work in alkaline solutions.In the presence of air, the molten base can oxidize tungsten into tungstate, and in the presence of oxidizing agents (NaNO3, NaNO2, KClO3, PbO2), the reaction to produce tungstate is even more violent.It can be combined with oxygen, fluorine, chlorine, bromine, iodine, carbon, nitrogen and sulfur at high temperature, but not with hydrogenation.
Important use of tungsten
Tungsten is widely used in modern technology both in pure metal state and in alloy state. The main states in alloy state are alloy steel, cemented carbide based on tungsten carbide, wear-resistant alloy and hot alloy.Tungsten is mainly used in the following industrial fields:
Tungsten carbide has high hardness, wear resistance and refractory.These alloys contain 85 percent to 95 percent tungsten carbide and 5 percent to 14 percent cobalt, a binder metal that gives the alloy the necessary strength.
The hardest metal to melt, tungsten, is a component of many heat-strong alloys, such as 3% -- 15% tungsten, 25% -- 35% chromium, 45% -- 65% cobalt, and 0.5% -- 0.75% carbon. It is used mainly for strongly wear-resistant parts, such as valve doors for aeroengines, working parts for die presses, turbine blades, excavators, and surface coatings for plows.
Alloys of tungsten and other refractory metals (such as tantalum, niobium, molybdenum, and rhenium) are used as heat-strong materials in aerospace rocket technology and in other sectors requiring high thermal strength in machine parts, engines, and some instruments.
It is these properties of tungsten that make it the focus of material research in fusion reactors, especially the retention of hydrogen and its isotopes in tungsten.
Important strategic metals
Tungsten is a rare metal.Rare metals are usually metals that are found in low or dispersed quantities in nature.Tungsten is a widely distributed element found in almost all types of rocks but in low levels.The content of tungsten in the crust is 0.001%, and the average content in granite is 1.5×10-6.
This characteristic makes it very difficult to extract, usually can only be separated by organic solvent extraction method and ion exchange method.With the progress of science and technology, the development of metallurgical technology, equipment, analysis and detection technology and the expansion of rare metal production scale, the purity of tungsten has been continuously improved, the performance has been improved, the variety has been increased, thus expanding the applicat
ion field of tungsten.China is rich in tungsten mineral resources, the output and export of tungsten occupies the first place in the world.
Tungsten is a strategic metal.It is well known that rare metals are important strategic resources of a country, and tungsten is a typical rare metal with extremely important USES.
It is an important part of the modern high-tech new materials, a series of electronic optical materials, special alloys, new functional materials and organic metal compounds, etc. need to use the unique properties of tungsten.The dosage is not large, but it is essential.Therefore, it is widely used in modern communication technology, electronic computer, aerospace development, medicine and health, photosensitive materials, photoelectric materials, energy materials and catalyst materials.
