Scientists led by physical chemist Rodney Ruoff of the Institute for Basic Science in South Korea published their results in the journal Nature on April 24, revealing that they can grow diamonds from scratch in 15 minutes.
Researchers have developed a novel method for creating diamonds at room temperature and without the need for an initial gem, which may greatly simplify the process of growing priceless stones in a laboratory.
The Earth’s mantle, the molten zone hundreds of miles below the planet’s surface, is where natural diamonds are formed. Under extreme pressure of many gigapascals and extreme heat reaching 2,700 degrees Fahrenheit (1,500 degrees Celsius), the process occurs.
The process now applied to generate 99 percent of all synthetic diamonds uses similar circumstances. The process known as high-pressure and high-temperature (HPHT) growth makes use of these harsh conditions to induce the conversion of carbon dissolved in liquid metals, such as iron, into a diamond around a tiny seed, or beginning diamond.
Nevertheless, it is challenging to create and sustain the high temperatures and pressures. The size of the diamonds is also influenced by the constituents; the largest is roughly the size of a cubic centimeter, or roughly equivalent to a blueberry. Furthermore, even these small jewels require a week or two of HPHT processing time. Chemical vapor deposition is an alternative technique that does away with some of the high-pressure needs of HPHT. Some, nevertheless, like the hunger for seeds, never go away.
The new method gets rid of some of the shortcomings of both synthesis methods. The results of a team led by physical chemist Rodney Ruoff of the Institute for Basic Science in South Korea were released in the journal Nature on April 24.
The diamond crucible
It took a while to develop the innovative technique. “For over a decade I have been thinking about new ways to grow diamonds, as I thought it might be possible to achieve this in what might be unexpected (per ‘conventional’ thinking) ways,” Ruoff stated in an email.
Initially, the scientists utilized gallium and a small amount of silicon heated electrically in a graphite crucible. Despite its unusual name, gallium was chosen for this project because earlier research on unrelated topics revealed that it may promote the conversion of methane into graphene. Similar to diamonds, graphene is made entirely of carbon atoms arranged in a single layer as opposed to the tetrahedral orientation found in gemstones.
The crucible was kept at sea level air pressure by the researchers in a specially constructed chamber that allowed for the flushing of extremely hot, carbon-rich methane gas. This 2.4-gallon (9-liter) container, designed by co-author Won Kyung Seong of the Institute for Basic Science, could be prepared for experimentation in only 15 minutes, enabling the researchers to quickly do runs with varying concentrations of metals and gasses.
By making these adjustments, the scientists discovered that the best combination for stimulating the creation of diamonds was gallium, nickel, and iron, along with a small amount of silicon. In fact, in just fifteen minutes, the team was able to extract diamonds from the base of the crucible using this mixture. A more comprehensive diamond film formed in 2.5 hours. Spectroscopic examination revealed that the majority of this film was pure but contained a few silicon atoms.
The exact process that created the diamonds is still mostly unknown, but scientists believe that carbon from the methane is driven toward the center of the crucible by a reduction in temperature, where it coalesces into diamonds. Additionally, since silicon is necessary for the formation of diamonds, scientists believe it could serve as a seed for the carbon to crystallize around.
The new approach is not without its difficulties, though. One issue is the modest size of the diamonds produced using this method; the largest ones are hundreds of thousands of times smaller than those produced using HPHT. They are therefore too little to be worn as diamonds.
The diamonds created using the novel method may have other applications, such as in more technical fields like drilling and polishing. Still, Ruoff noted that the low pressure involved in the process could lead to a major scaling up of diamond synthesis.
“In about a year or two, the world might have a clearer picture of things like possible commercial impact,” he stated.
Last year, GreatGameIndia reported that, according to Bloomberg, Amazon has partnered with De Beers to grow synthetic diamonds for quantum computing.
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