Last month, comic book fans flocked to cinemas as Black Panther hit the screens. Underpinning the film's plot was fictional metal vibranium, which powered the titular hero's kingdom of Wakanda. Interestingly, this metal was, in part, inspired by tantalum. So, what of the marvellous metal's real-life counterpart? Here, Heiko Wildner, refractory metals specialist for materials comparison site Matmatch, examines the value and considerations of using tantalum.
Just as Black Panther's vibranium was pivotal to the plot of the movie and the franchise itself, tantalum is similarly important to our modern society. In fact it is almost inevitable that you are currently sat mere inches away from a piece of tantalum.
A refractory metal found predominately in African countries, tantalum's most common application is as a capacitor in electronic circuits — the same kind you would find in a mobile phone. The reason for tantalum's popularity in this application is due to its chemical properties.
At high temperatures, generally around 500degC, tantalum experiences oxidation and forms a surface layer of tantalum pentoxide (Ta2O5), which is the key to its wide range of applications. And in contrast to Wakanda, the tantalum community is well known and organised in the Tantalum and Niobium International Study Center (TIC).
From capacitors to jet engines
For use in capacitors, tantalum is powdered and compressed into a pellet shape to serve as a plate, with a Ta2O5 top layer to serve as a dielectric and an electrolytic solution to complete the capacitor. The connecting wires are also made of tantalum metal. In this form, tantalum electrolytic capacitors provide high capacitance with a relatively small footprint, making them a popular choice for modern electronics like mobile phones, computers and in-car electronic devices.
While tantalum is most commonly used in capacitors, its properties also make it suitable for a range of other applications. For example, tantalum is highly resistant to chemical corrosion - for example, against sulphuric acid - even at elevated temperatures.
These properties make tantalum an effective metal for use in chemical reactors, particularly in the pharmaceutical, water treatment and process industries. As with other refractory metals, it can also withstand very high temperatures, which allows it to be used in extreme environments such as jet engines.
Perhaps most interesting is the use of tantalum in healthcare, particularly for implants and bone replacement material in prostheses. The metal is also highly biocompatible, so it can be used in humans without causing adverse effects, and its corrosion resistance makes tantalum immune to bodily fluids. It is often selected for being hard and ductile, but implant designers should bear in mind the material's high density.
However, not all tantalum is created equal. When specifying the metal, design engineers and product designers must do more than simply select the shape, dimensions and length of the material. Due to its classification as a conflict resource, tantalum should only be selected from a supplier that can prove it was sourced ethically.
Matmatch ensures its tantalum suppliers hold certification from the Electronic Industry Citizenship Coalition (EICC). This certificate, while optional for suppliers, is proof that the material provided by that supplier is ethically sourced and manufactured in a responsible manner.
Some suppliers, such as Plansee, refer to this as being 'conflict-free' tantalum because it does not originate in regions of conflict and does not contribute to the exploitation of those mining the material.
While it might not facilitate the same advanced technology as vibranium does in Black Panther, tantalum is a key material in the development of modern technology and society. By considering its properties and sourcing it ethically, materials engineers and product designers make the right decision with their materials.
If you are considering using tantalum for a project, you can compare types and identify suppliers using the Matmatch online materials database. Follow the link to view the range of tantalum available.