A diamond in the anvil used by the scientists to make nano-sized Lonsdaleite. Photo: Jamie Kidston, ANU.
A diamond in the anvil used by the scientists to make nano-sized Lonsdaleite. Photo: Jamie Kidston, ANU.

The Australian National University (ANU) has led an international project to make a diamond that's predicted to be harder than a jeweller's diamond and thus useful for cutting through ultra-solid materials on mining sites.

As they report in a paper in Scientific Reports, ANU associate professor Jodie Bradby and her team have developed a way to synthesize nano-sized Lonsdaleite. This is a hexagonal diamond that in nature is only found at the site of meteorite impacts such as Canyon Diablo in the US. It is named after the famous British pioneering female crystallographer Dame Kathleen Lonsdale, who was the first woman elected as a Fellow to the Royal Society.

"This new diamond is not going to be on any engagement rings," said Bradby. "You'll more likely find it on a mining site – but I still think that diamonds are a scientist's best friend. Any time you need a super-hard material to cut something, this new diamond has the potential to do it more easily and more quickly."

Her research team made the Lonsdaleite in a diamond anvil at 400°C, halving the temperature at which it is normally formed in the laboratory.

"The hexagonal structure of this diamond's atoms makes it much harder than regular diamonds, which have a cubic structure," explained Bardby. "We've been able to make it at the nanoscale and this is exciting because often with these materials 'smaller is stronger'."

Co-researcher Dougal McCulloch from RMIT explained how collaboration between world-leading experts in the field was essential to the project's success. "The discovery of the nano-crystalline hexagonal diamond was only made possible by close collaborative ties between leading physicists from Australia and overseas, and the team utilized state-of-the-art instrumentation such as electron microscopes," he said.

Corresponding author David McKenzie from the University of Sydney described how he was doing the night shift in Oak Ridge National Laboratory in the US as part of this research when he noticed a little shoulder on the side of a spectral peak. "And it didn't mean all that much until we examined it later on in Melbourne and in Canberra – and we realized that it was something very, very different."

This story is adapted from material from Australian National University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.