Science and technology

It’s not surprising that most people think of gold as an expensive, luxurious metal. You only need to read about gold’s extraordinary history to see how that came to be. But gold has an alter-ego – as an incredibly versatile and useful material in science and technology. In fact, our ever-expanding use of technology has actually been a major factor in recent increases in the demand for gold.

Electronics

Did you know the humble touchtone telephone typically contains 33 gold-plated contacts? Gold’s main role in electronics is in contacts, switches, relays and connectors. Contacts are electroplated with a very thin film of gold. This touch of gold on a contact ensures rapid dispersion of heat, and also works to stop oxidation or tarnishing at extreme low or high temperature, providing an atomically clean metal surface with an electrical contact resistance close to zero.

Gold's other main role in electronics is in semiconductor devices, where fine gold wire or strip is used to connect parts such as transistors and integrated circuits, and in printed circuit boards to link components. Again, the need for reliable connections makes gold indispensable. This bonding wire is one of the most specialised uses of gold; it’s highly refined to more than 99.9% purity, and the wire has a typical diameter of one hundredth of a millimetre.

Space and aeronautics

Without gold, man wouldn’t have visited the moon. Gold, in the form of sheets 0.15mm thick, are used in space programmes as a radiation shield. Because gold is such an effective reflector, it deflects the burning heat of the sun.

Gold is central to safe space travel, so its demand has obviously grown as the space industry has. For example, more than 40.8 kilograms of gold was used in the construction of the famous US Columbia space shuttle, mainly in brazing alloys, fuel cell fabrication, coated plastic films and electrical contacts.

Nanotechnology

Scientists working in nanotechnology have tended to build their nanostructures using carbon, which actually attaches itself to other substances more or less indiscriminately, whereas gold is much more reliable in that respect. JP Behrens of wealthdaily.com has described gold’s advantages:

‘Unlike carbon, gold doesn't attach to everything, but only to specific areas. It finds points to attach to, and limits where it settles. Once it chooses to settle, technicians can find the spots and attach materials to them with ease... This new precision allows nano-architects to use more meticulous actions in building newer materials faster.’

Catalysts

Catalysts are substances or materials which accelerate the rate of a chemical reaction without being consumed by the reaction themselves. They’re an essential component of many different industrial processes used to produce chemicals, foodstuffs and other materials. Perhaps one of the first intentional uses of catalysis was in the fermentation of sugar to make alcohol. Another common example is the use of catalytic converters on cars, to control exhaust emissions.

Until recently, most researchers had overlooked gold as a possible industrial catalyst. However, there is now a growing anticipation about gold’s potential for catalysing industrial reactions, largely thanks to the recent work of Graham Hutchings at the University of Wales, and Masatake Haruta from AIST in Japan.

One of the most remarkable things about catalysis by gold is the low temperature at which it becomes functional. Gold catalysts operate best between 200-350K°, whereas platinum needs temperatures between 400-800K° to work properly. Gold also offers the potential to catalyse new reactions, and can in some cases be surprisingly cost-effective.