Researchers conjure up ultra-light ‘black gold’

29 Mar 2016

A team of South Korean researchers are verging on claims of alchemy with the news that it has developed a new material dubbed ‘black gold’, with its properties showing it to be twice as solid as gold, but 30pc lighter.

This ‘black gold’ – or going by its official name, nanoporous gold (np-Au) – is a new material developed by researchers from the Ulsan National Institute of Science and Technology (UNIST) that could have a multitude of different uses in the manufacturing industry over actual gold.

According to EurekAlert, the team, led by Prof Ju-Young Kim, has now published a paper in Nano Letters that details the unusual properties of np-Au, explaining that they are dubbing it black gold due to the fact that at sizes of less than 100 nanometres the rough material turns black.

The research team was able to develop np-Au by using a ball-milling technique to increase the flexural strength of the three gold-silver precursor alloys and then using free corrosion dealloying of silver from gold-silver alloys, creating the nanoporous surface.

Black gold diagram

These images show the formation of nanoporosity in free corrosion dealloying for gold samples. Image via UNIST

Np-Au has actually been found to be much more useful as a material to use than its shinier counterpart, with it being 30pc lighter than its natural cousin and twice as dense.

Additionally, np-Au has been found to have a 100,000-times wider surface when compared to standard gold and is much more chemically stable, making it completely harmless to humans.

Prof Kim and his research team now suggest that the same technique used to create black gold can be also applied to many other metals, as the np-Au produced by this technique has shown increased strength and durability while still maintaining the good qualities of standard gold.

In terms of what industries could soon use black gold in its manufacturing process, it’s likely to be catalytic converting technologies.

Gold liquid image via Shutterstock

Colm Gorey was a senior journalist with Silicon Republic