Tungsten is a rare metal that can’t be found naturally, requiring extraction from mineral ores. As one of the hardest and most resistant refractory metals, many industries use tungsten in various forms to create long-lasting parts for all kinds of equipment.
It’s so sought-after because the stability of tungsten makes it suitable for complex applications in difficult environments, from medical research to the aerospace industry. There are many different ways to use tungsten, which can range from days to decades of use.
This blog explores how long tungsten metal lasts in common situations and how you can expect this element to react to changing environmental conditions, explaining why tungsten is in high demand.
What is the lifespan of tungsten?
Natural tungsten, with the atomic symbol W, is made up of five isotopes (W-180, W-182, W-183, W-184, and W-186). While they can eventually decay into isotopes of a different element over time, the half-lives of these isotopes are so long that they’re practically stable.
This means that the majority of natural tungsten isotopes decay so gradually that they can last for a minimum of 4.1×1021 years, according to the CRC Handbook of Chemistry and Physics. That’s four sextillion – a number so big it can be hard to wrap your mind around it.
Of course, tungsten is rarely used in its pure form, so the lifespan of the metal depends on the particular compound it becomes a part of. Additionally, when artificial tungsten radioisotopes are formed for radioactive applications, their half-lives can be as short as three weeks.
Though it has extremely high resistance to heat and corrosion, how long tungsten lasts depends on the specific usage of the specific compound. Factors like excessive pressures and exposure to other elements in their working environment can shorten the lifespan of tungsten components.
Does tungsten shatter?
According to the Mohs hardness scale, which determines the scratch resistance of minerals, tungsten is one of the hardest metals. If diamond is at the top of the hardness scale at 10, tungsten sits not far below at 8, with tungsten carbide even higher at 9.
This means that diamond is one of the only things that can scratch tungsten, and that this metal doesn’t deform easily (if at all). However, if you’ve heard that tungsten is indestructible, this is sadly a myth. Even tungsten can crack and break under enough force.
While it’s very hard and resistant to scratching, bending, melting, and corroding, tungsten is actually quite brittle. Though pure tungsten can be soft and malleable enough to work with, it becomes a hard and brittle metal that can shatter if you apply enough pressure or shock – which is why it’s often alloyed with other elements to make a stronger compound.
Does tungsten rust?
Other than precious metals like gold, most metals rust when exposed to air and moisture. This is a chemical reaction known as oxidation that takes place on the metal’s surface, corroding some of the metal to form a metal oxide coating. This is the cause of the discolouration known as tarnishing.
When it comes to tungsten, it generally doesn’t react to oxygen or water at room temperature. Its high resistance to heat and acidic corrosion means that tungsten oxidation only happens at elevated temperatures. While oxygen can begin to react with the surface below 200°C, layers of tungsten oxide only build up from 600–800°C, eventually developing into tungsten trioxide.
Unless the component is going to be enduring these kinds of temperatures, you don’t have to worry about tungsten oxidising. However, if you have a tungsten alloy that uses a more reactive metal as a binder, like cobalt, then it may be prone to oxidisation and rusting when exposed to air and water.
Is tungsten carbide stronger than pure tungsten?
One of the most popular forms of tungsten is a compound formed with carbon, making it much stronger than common construction metals like steel and titanium. Tungsten carbide is up to 3 times as rigid and 100 times as long-lasting as steel.
Where lesser metal compounds will weaken and break much faster, tungsten carbide is almost as hard as diamond and difficult to wear down, making it an attractive and cost-effective material for drilling and cutting tools.
Its superior tensile strength, high density, and extremely high heat resistance makes this material the most commonly used cemented carbide in the manufacture of high-speed tools.
Tungsten carbide is also easier to mine and machine, as pure tungsten is too soft and ends up compacting into smaller spaces, eventually rendering expensive diamond cutting tools unusable.
While it’s often believed that tungsten carbide oxidises much faster than pure tungsten, it actually fares better than tungsten at higher temperatures, outperforming above 900°C.
Can tungsten be recycled?
Since it has such a long life, many forms of tungsten are easy to recycle and reuse. For example, it’s possible to collect tungsten metal scraps to melt them down and reform them into something else.
Other metals might lose their integrity or become unsalvageable after enduring too much damage, while the long-lasting strength of tungsten allows it to be recycled over and over again.
Tungsten may not have a high resale value like precious metals, but it’s still a rare refractory metal with a higher demand than availability, and one of the strongest and longest-lasting metals out there. Across most industries that require durable metal components, you can’t beat tungsten.
