Observations made from a transmission electron microscope revealed that the gold object’s surface molecular structure has started to lose the order they previously held. They found three layers of gold atoms that have started moving around, which is clear evidence of the process of melting.
Prior, electric fields have been used by researchers to sublimate gold from a solid to a gas.
The scientists, awestruck by the never-before-observed phenomenon, have also found that decreasing the electric field can restore the gold object back to its original solid state. The team at Chalmers also plans to learn whether this method can be applied to much harder types of metals.
Their findings were published as an article in the journal Physical Review Materials.
A matter of heat
Melting gold is not an easy affair. The melting point of pure gold is at 1,064 degrees Celsius (or 1,948 degrees Fahrenheit), with the boiling point of the element at a whopping 2,700 degrees Celsius (5,173 degrees Fahrenheit). In practice, the melting point of gold objects and ore can vary significantly, depending on the presence of other metallic elements.
The researchers at the Chalmers Institute, however, point to an alternate means of liquefying solid metals like gold. Computational modeling and microscope imagery shows that the experiment’s results were not derived from increasing temperature but from applying high electrical fields to the surface of the gold objects. The electrical field, once high enough, interferes with the crystalline structure of the gold, causing the atoms to shift around and liquefy.
In addition, the gold returns to its crystalline solid state once the strength of the electric field has been diminished.
The demonstrated principle of melting gold and returning to its original structure without resorting to applying heat may pave the way toward exciting new developments. This new technology can be applied to a diverse array of fields ranging from chemical engineering to optical science. A few of the prospective new technologies that can be derived from electrical field melting include sensors, contactless components in machinery, and chemical catalysts for various applications.
Despite the exciting prospects, however, the new discovery’s practical applications are far from clear at this point, with one of the challenges being the scale it needs to accomplish to be a practical technology.
Among these scale challenges include the size of the energy field required in melting gold. Melting the first two or three atomic layers in the nanocones required more than 25,000,000,000 volts per meter, even when they used at most 100 volts. And because gold is softer than most metals, the voltage required to melt other metals this way may be even higher.
The gold cones used were also minuscule. This signifies a greater challenge in scaling this new technology. Energy field engines that can melt large metallic objects are likely too impractical to feasibly consider due to the lack of sufficient voltage to make it a reality. Feasible projects incorporating this principle would make them largely ideal for nanotechnology, where the mechanisms in place are too small for humans to see.