With the highest melting point among metals, tungsten has low thermal expansion coefficient and extremely high shape stability even under a super high temperature environment.
For its relatively large electric resistance, we offer tungsten rods for various discharge electrodes, which have improved discharge property and discharge consumption resistance.
Although tungsten is a metal with high hardness, its hardness is enhanced by combining it with carbon; it is used for high-grade cutting tools.
Tungsten, meaning “heavy stone” in Swedish, is a very hard and heavy silver gray rare metal. With the highest melting point among metals, tungsten has a relatively large electric resistance as a metal, so it is used for heaters and reflectors and the like in furnaces exceeding 2000℃.
It also becomes a hard alloy when mixed with carbon, etc. Cemented carbide combined with cobalt is used for high-grade cutting tools.
In addition, tungsten, with extremely low environmental impact, has a very high radiation shielding capability compared to lead; it is also widely used as radiation shielding material in medical field such as X-ray CT.
Tungsten does not seem familiar to us in our daily life, but it is closely related to our lives for its industrial and medical uses.
|Linear expansion coefficient
|Thermal neutron capture cross section area
|700℃||Produces WO3 and rapidly oxidizes|
|530℃||Produces WO3 even at low pressure|
|Oxidation progresses rapidly|
|Nitrogen||No reaction up to 2,000℃|
|Three stages of absorption up to 1,700°C|
|Dry chlorine||250℃||Produces 6 chloride|
|Produces sublimable fluoride|
|Bromine||Red heat||Produces bromide|
|Iodine||Red heat||Produces bromide|
|Red heat||Surface reaction occurs|
|Hot liquid||No reaction|
|No reaction for dilute/concentrated|
|Hot liquid||A little corrodes|
|Dilute sulfuric acid||Room
|Hot liquid||Slightly corrodes|
|Hot liquid||Gradually corrodes|
|Sulfuric acid||Hot liquid||Slightly corrodes|
|Hydrofluoric acid||Hot liquid||No reaction for dilute/concentrated|
Sulfuric acid＋hydrofluoric acid
|Hot liquid||Rapidly corrodes|
|Aqua regia||Hot liquid||Slightly dissolves producing oxide film|
|Accelerated in air by oxidation|
|Sodium nitrite||about 500℃||Melts while violently generating heat|
|Liquid ammonia||Not corrode|
|Carbon, graphite||850 to 1,410℃||Absorbs carbon|
|1,410 to 1,600℃||Produces carbides|
|Magnesia||up to 1,500℃||Stable|
|Zirconia||up to 1,600℃||Stable|
|Thoria||2,200℃||Reduces thoria slightly|
|Alumina||up to 1,900℃||Stable|
|Beryllia||up to 2,200℃||Stable|