Swedish Researchers Melt Gold At Room Temperature

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The illustration shows the atoms of a gold cone exposed to a strong electric field. We also see the field (around the tip of the cone) that excites the gold atoms. They break almost all their connections to each other and the surface layers begin to melt. (Credit: Alexander Ericson)

In its purest form, gold typically requires temperatures of 1,948 degrees Fahrenheit (1,064 degrees Celsius) to liquefy. Now, a team of researchers from the Chalmers University of Technology in Sweden may have stumbled upon a way to melt the precious metal at room temperature.

For those not clear on the physics behind the phenomenon of melting, here is a brief tutorial. Solids, as you may know, can maintain size and shape under constant conditions because their atoms, or molecules, do not have enough energy to pull apart. When an external source of energy is introduced, it gets the molecules excited and causes the tight structure to break down, allowing them to start moving freely. This results in a change of state from solid to liquid, or what we refer to as melting. Researchers mostly use heat, or in some cases pressure, to trigger the change. However, the Swedish team managed to accomplish the feat using a different energy source – an electric field.

The arrangement of water molecules in the three states (Credit: University of Wakato/Sciencelearn.org,nz)

For their study, Dr. Ludvig de Knoop and his team placed a gold sample under an electron microscope (EM). Unlike optical microscopes that depend on visible light, EM’s use a beam of accelerated electrons as a source of illumination, making them powerful enough to see individual atoms. To investigate if the electrical field had any impact on the metal’s molecules, the researchers gradually increased its intensity while using the highest magnification.

"We wanted to see what happens to gold when it is under the influence of an extremely high electric field," de Knoop told Newsweek. "A known effect when applying such high electric fields on metals is that they evaporate, that is, they boil off from the solid metal."

Upon examining the atoms in recordings taken from the EM, de Knoop noticed something very unexpected – the surface layers of the gold sample had melted, even though the experiment had been conducted at room temperature. The change was easily reversed by simply turning off the electric field.

Optical microscope vs. electron microscope (Credit: embryology.med.unsw.edu.au/CC BY-SA 3.0)

"It wasn’t until later, when we analyzed the data and the recorded movies, that we understood that we had witnessed something new and spectacular," de Knoop said. "The big surprise with our work was that the outermost few atomic surface layers of gold melted before they evaporate.”

The researchers, who published their findings in the journal Physics Review Materials on August 22, 2018, believe the electrical field caused the gold atoms to become excited and lose their structure, breaking the strong bond between them. However, de Knoop said, “IIt is] Important to note is that it is only the 2-3 outmost atomic layers that experience the electric field, further into the gold cone the electric field is zero and the atoms are ordered and structured in their usual way. This is an important difference compared to melting gold by increasing the temperature."

Though the technique needs to be investigated further, the team believes it could help revolutionize the field of material sciences and have numerous applications in the development of nanodevices like sensors, catalysts, and transistors. “There could also be opportunities for new concepts for contactless components," said study co-author Professor Eval Olsson.

Resources: Newatlas.com,Sciencedaily.com,Newsweek.com

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466 Comments
  • huskyfoxy
    huskyfoxyWednesday, April 28, 2021 at 8:22 am
    it's cool to know about this even though it's super complex for most of the "kids" it's super fascinating to know about the microscopic things around us. The universe works in it's ways and I hope that one day will be able to investigate how the sun works! Since we can't travel to it because of it's gravity, etc. It would be very awesome we could understand how "space particles" are alive and keep working!
    • epowell77
      epowell77Tuesday, April 20, 2021 at 1:51 pm
      This is so cool even though i know most of this
      • kittycorn27906
        kittycorn27906Saturday, February 13, 2021 at 11:27 am
        im doing this for school but its still cool to know
        • epowell77
          epowell77Tuesday, April 20, 2021 at 1:54 pm
          I'm also doing this for school. it's a long assignment though >:(
        • erikislindo
          erikislindoTuesday, November 3, 2020 at 12:00 pm
          Wow that’s investing I did not know that
          • erikislindo
            erikislindoTuesday, November 3, 2020 at 11:59 am
            Wow
            • conner765s
              conner765sTuesday, October 27, 2020 at 1:33 pm
              omg thats so cool and the fact that you can make a millon bucks with that
              • trekTuesday, October 29, 2019 at 4:15 pm
                I didn't know that gold melt at room temperature.
                • bubbers22
                  bubbers22Monday, October 28, 2019 at 8:30 pm
                  That is weird how gold melts under extreme energy. Like the article said usually only substances melt under lots of heat or in some cases pressure. However, the gold melted just like that under all of those concentrated electrons. I wonder why the gold specifically melts under all of the energy when most metald would not. Anyone got any ideas why? Let's make some hypothesizes.
                  • LCCSunday, October 27, 2019 at 6:46 pm
                    I have homework because of this article! :(
                    • Someone Monday, August 5, 2019 at 8:10 am
                      This article melted my mind!