As one of the most popular refractory metals, there are many uses for tungsten metal. This shiny silver-white metal has one of the highest melting points and densities of all metals, making it an excellent resource for strengthening other materials.
Since tungsten does not occur naturally as a metal, it has to be formed after extracting it from tungsten ores and processing it. There are dozens of ways to produce and use pure tungsten, or to incorporate it into alloys, carbides, or tungsten-based chemicals.
This blog will run through the popular uses of tungsten around the world, both throughout history and in modern life, showing you why this element is the king of the refractory metals.
Useful Properties of Tungsten
Before we look into the various specific uses of tungsten, you’ll need to understand more about the properties that make it such a desirable and versatile material. Here are some quick facts about the element from the Royal Society of Chemistry (RSC) and Britannica Encyclopedia:
- Melting point = 3414°C (6177°F or 3687 K)
- Boiling point = 5555°C (10031°F or 5828 K)
- Occurs in the Earth’s crust at 1.5 parts per million (1.5g per ton of rock)
- Most common ores are scheelite, wolframite, and stolzite
- Naturally a mix of five stable isotopes, making it relatively inert
As a hard and dense yet ductile material, which is also highly resistant to high temperatures and corrosion, it’s not surprising that tungsten’s qualities make it so useful in so many industries.
Here are some examples of tungsten properties and how the metal can be applied:
- Low thermal expansion – aerospace parts (engines, rotor blades), glass-to-metal seals
- Low sensitivity – high-purity jewellery as a substitute for similarly dense gold or platinum
- High density – security and medical radiation shielding, counterweights, military missiles
Read on for more details on how tungsten is used in a range of industries and forms.
Tungsten in Electronics
There are many properties of tungsten that make it the top choice for electron emitters and other electrical contact materials. For example, while copper or silver would evaporate and erode under electric arc conditions, tungsten can easily withstand these, maintaining a low vapour pressure at high temperatures.
Its high plasticity, electron emissions, and heat resistance make tungsten ideal for manufacturing integrated circuit parts for all kinds of electronics. Tungsten acts as a contact material between silicon dioxide dielectrics and transistors. It’s often found in a range of consumer appliances, from televisions, phones, and computers to refrigerators, microwaves, and smoke detectors.
It can also be found in vacuum tube filaments, cathode-ray tubes for X-rays, electron microscopes, and many more products with electrical components. Tungsten can also be used with copper to create heat sinks that prevent microelectronic devices from overheating.
Tungsten Light Bulbs
One of the most popular electrical uses for tungsten and probably the most widely known is light bulb filaments. Since the early twentieth century, tungsten metal has been drawn into thin wires to be used in incandescent bulbs, with the lamp industry being its largest commercial application.
Despite their high heat resistance, electrical conductivity, and vapour resistance, this type of old-school light bulb has been phased out in many places in favour of more energy efficient LEDs. Today, tungsten filaments can still be found in strong artificial lighting in industrial and medical settings.
You can find tungsten light filaments in camera and projector reflectors, compact fluorescent lamps, and high-intensity discharge lamps, which are also often used in the entertainment industry.
Another common type of tungsten used since the nineteenth century is the alloys created in steel production. Since tungsten is so dense and hard, it can be used to strengthen steel and improve its wear resistance. This increases the hardness and cutting capacity (efficiency and speed) of the steel.
While steel remains one of the biggest markets for tungsten, there are lots of other tungsten alloys with other metals. The tougher element can be mixed with copper, silver, iron, cobalt and more to enhance strength, corrosion resistance, and other crucial qualities for various industrial purposes.
Alloyed tungsten can be found in various high-density items like turbine blades, ballasts, weights, darts, and deflector shields, as well as heat-resistant applications like rocket engine nozzles and high-speed cutting blades. Steel components made from steel-tungsten alloys tend to have around 18% tungsten, but alloys have to contain at least 90% tungsten to be considered heavy metals.
When you heat a mix of tungsten powder and carbon powder, you produce a tungsten alloy known as tungsten carbide. This half-carbon compound is denser and harder than steel and titanium, almost as hard as diamond, which makes it useful for manufacturing cutting and drilling tools.
Where steel would wear out and break down after a while of cutting tougher materials, tungsten carbide is more durable. This makes it the better choice for heavy-duty tools like drill bits and saw blades in the mining, machining, metalworking, and construction industries, among many others.
If tungsten carbide isn’t quite what your project needs, combining it with another metal alloy under high heat and pressure can form cemented carbides. Also known as hard-metal, tungsten cemented carbide combines the toughness of tungsten carbide with the qualities of cobalt, nickel, or iron. These carbides are mainly used for high-speed cutting and milling tools.
Chemical Applications of Tungsten
Though the percentage is small compared to tungsten alloys and carbides, the element still has its uses in the chemical field. Tungsten oxides and tungsten sulphides, tungstates and tungstic acids – all of these and more can be found in industries such as medical, oil, lubricants, and electronics.
For example, since the treatment of crude oils became a booming industry alongside the invention of motor vehicles, tungsten sulphide became a key chemical as a catalyst in gasoline synthesis. In coal-fired power plants, tungsten oxide is also used as a selective catalytic reduction (SCR) catalyst.
As coloured compounds, tungsten oxides can also be used to make organic pigments for paints and clothing dyes, while tungsten compounds with magnesium or calcium can create phosphors to make powdered pigments fluorescent. Tungsten-based chemicals can also be used to make X-ray screens.
Tungsten even has biochemical uses, as sodium tungstate is found in laboratories as a reagent. It can not only separate minerals based on density, but can also help bacteria to create an enzyme that can reduce carboxylic acids to aldehydes, making it the heaviest metal that has a biological role.
Tungsten and Future Technologies
Scraps containing tungsten can be chemically processed and recycled, allowing waste such as carbide turnings and powder from the tooling industry to be recycled. This helps to boost the eco-friendliness of tungsten metal, but it could contribute even more to the planet’s wellbeing.
When it comes to the efficient production, storage, and consumption of energy, tungsten-based materials could play a big part in fuel cells and energy-saving technology. Tungsten has had a long history in the fossil fuel industry, so it’s time to focus on how tungsten’s useful properties can help with generating and distributing renewable power, instead.
Tungsten might also make some incredible changes to the medical industry if current research comes to fruition. Researchers are currently studying the use of tungsten polyanions in cancer treatments for suppressing tumours and the proteins in the brain that causes Alzheimer’s.
Research is also ongoing into electromechanical prostheses for severely disabled patients, where tungsten micro-needle sensor arrays could help them to control prosthetic limbs with an electronic control system implanted in the brain.
With so many purposes for tungsten and so many more potential uses that could change modern life as we know it, it’s safe to say that this is one essential element to keep an eye on.