South Korean Scientists Create Diamond Thin Films at Atmospheric Pressure

Natural diamonds take billions of years to form deep within the Earth under extreme pressure and temperature. Artificial diamonds can be made much faster, but their production also typically takes several weeks.

However, a new method for making diamonds has been developed that is based on a mixture of liquid metals and can produce artificial diamonds in a matter of minutes. This method also does not require high pressure.

While the production of the new artificial diamond still required high temperatures (in the range of 1025 degrees Celsius), a continuous layer of diamond was produced under atmospheric pressure in 150 minutes. This pressure is equivalent to the pressure we feel at sea level and tens of thousands of times lower than the pressure usually required to make diamonds.

Researchers at the Korea Basic Science Institute, who discovered this innovative approach, are confident that the new process can be scaled up for the production of artificial diamonds.

Dissolving carbon in liquid metal to make diamonds is not a completely new method. For example, General Electric developed a process using molten iron sulfide half a century ago. But these processes still required pressures of 5 to 6 gigapascals and a diamond seed for carbon to adhere to.

“We have discovered a method for growing diamonds at atmospheric pressure and under moderate temperature using a liquid metal alloy,” the researchers write in their paper.

The pressure reduction was achieved by using a precise combination of liquid metals gallium, iron, nickel, and silicon. A custom vacuum system was created inside a graphite chamber to rapidly raise and then lower the temperature when the metal was exposed to a mixture of methane and hydrogen. These conditions cause the carbon atoms in the methane to diffuse into the molten metal and act as diamond seeds. After 15 minutes, tiny pieces of diamond crystals emerged from the liquid metal below the surface, while after two and a half hours, a continuous layer of diamond was formed.

Although the carbon concentration forming the crystals decreased to a depth of several hundred nanometers, the researchers believe that the process can be improved with a few tricks. According to their suggestions, changes such as using a larger surface area, configuring the heating elements to achieve a larger growth zone, and distributing carbon in the diamond growth region could improve the process. Of course, these changes will take time and research on them is in its early stages, but the authors believe that they have high potential and that other liquid metals can also be used to achieve similar or even better results.

The process currently used to make most artificial diamonds (which are used for a wide range of industrial processes, electronics, and even quantum computers) takes several days and requires much higher pressure.

If the potential of the new technique is confirmed, it will make diamond manufacturing much faster and easier. Researchers say the liquid metal approach could accelerate diamond growth on different scales and perhaps even facilitate diamond growth on small diamond particles.

Back to top button