Tungsten is one of the hardest metals on the earth, and many scientists compare it to diamond. Tungsten is a dull silver-colored metal with the highest melting point of any pure metal. Pure tungsten melts at a whopping 6,192 degrees F (3,422 degrees C) and won’t boil until temperatures reach 10,030 F (5,555 C), which is the same temperature as the photosphere of the sun.
Also known as Wolfram, from which the element takes its symbol, W, tungsten is more resistant to fracturing than diamond and is much harder than steel. It is the refractory metal’s unique properties – its strength and ability to withstand high temperatures – that make it ideal for many commercial and industrial applications.
Tungsten also has the lowest co-efficient of thermal expansion of any pure metal. The low thermal expansion, high melting point and tensile strength of tungsten originate from strong metallic bonds formed between tungsten atoms. Thus, alloying small quantities of tungsten with steel greatly increases its toughness.
Tungsten’s primary application for over 100 years has been as the filament in incandescent light bulbs. Due to tungsten’s ability to keep its shape at high temperatures, tungsten filaments are now also used in a variety of household applications, including lamps, floodlights, heating elements in electrical furnaces, microwave ovens, x-ray tubes and cathode-ray tubes (CRTs) in computer monitors and television sets.
The metal’s tolerance to intense heat also makes it ideal for thermocouples and electrical contacts in electric arc furnaces and welding equipment. Applications that require a concentrated mass, or weight, such as counterweights, fishing sinkers, and darts often use tungsten because of its density.
In the quest to build a better and safer lithium-ion battery for use in cell phones, laptops and electric vehicles, a team of engineers at Rensselaer Polytechnic Institute in New York recently demonstrated how they could use aqueous electrolytes instead of the typical organic electrolytes to assemble a battery that still performs well. The breakthrough came from dense-packing niobium tungsten oxide particles in the battery’s electrode, which greatly improved its storage capacity without affecting its fast-charging capability, the researchers said. “It turns out that niobium tungsten oxide is outstanding in terms of energy stored per unit of volume,” said Nikhil Koratkar, who headed the research team at Rensselaer.
An inexpensive material, made from tungsten disulfide flakes just a few atoms thick, has helped to improve the performance of organic solar cells. The discovery by Saudi Arabian researchers could be an important step toward bringing these photovoltaic cells into wider use for generating clean electricity. The team found that the tungsten disulfide layer has a lower resistance than the conjugated polymer previously used, and is also better at gathering electron vacancies, or “holes” than the other materials, leading to improved performance.
In May 2020, a Hong Kong-California research collaboration reported building an artificial eye with capabilities that come close to those of the human eye. The artificial eye is made with an aluminum-lined tungsten Shell that serves as a round casing.
Metal 3D printing has become well-established and the range of metals that can be 3D printed is increasing quickly. Industrial 3D printer supplier ExOne Dec. 13 reported adding iron infiltrated with bronze and bonded tungsten to the range of metal and ceramic powders that can be used with its multi-material M-Flex machines. The company said one of the main reasons it has seen demand for using iron to 3D print parts instead of stainless steel is lower costs. Using bonded tungsten for 3D printing, ExOne collaborated with partner companies to produce products to replace lead parts in medical imaging and aerospace applications.
The European Commission recently recognized tungsten as having the highest economic importance of all raw materials. The mineral is already listed as critical in the United States, Japan, India and Australia.
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