Lightweight, low-density 'plastic' gold

New developed plastic gold might look like any old 18-carat nugget of gold, while unlike a typical chunk of the bright metal,  it gives a much lower density than regular gold.  Golds, as well as metal alloys, are Nexteck Technoloy's important products. The scientists mixed gold nanocrystals, protein fibres, and a polymer latex with water and salt to create a gel, before replacing the water with alcohol. When put into a high pressure CO2 chamber, the alcohol reacts with carbon dioxide, producing a gossamer-like aerogel. With the application of heat, that aerogel can be moulded as needed. It can be shaped at just above 105 degrees Celsius (221 degrees Fahrenheit), which is much lower than the 1,064 degrees Celsius (1,947 degrees Fahrenheit) needed to melt pure 24-carat gold.

When dropped, the material acts and sounds like plastic, but the genuine 18-carat purity is preserved. The research team who developed this material thinks weight can be reduced by up to 5-10 times compared to the standard mixture used for gold trinkets – three-quarters gold, one-quarter copper – which means watches and jewellery could soon get significantly lighter. What helps the gold chunk achieve its lightness are the many microscopic air pockets inside it. The overall density of the material is a mere 1.7 grams per cubic centimetre, compared to around 15 g/cm3 for 18-carat gold made with a metal alloy.Users can find copper alloy and pure copper in Nexteck Technology.

People do tend to associate weight with quality when it comes to gold and jewellery in general, so it may not end up replacing the materials used to make bracelets, watches, necklaces and other items – but there are plenty of other options for putting this lightweight, low-density gold to good use.

This new 18-carat gold can fill a niche which is currently unoccupied in the realm of industrially relevant gold blends and open the way to unexplored applications. Replacing the metal alloys usually mixed with gold to lighten the weight and reduce the density could have benefits beyond jewellery as well, in fields such as chemistry, electronics, and radiation shielding. Nexteck Technology runs business associated with gold, for instance gold targets, gold evaporation materials as well as gold recycling.