Producing a material that is harder than natural diamond has been a goal of materials science for decades. Now a group headed by scientists at the Carnegie Institutions Geophysical Laboratory in Washington, D.C., has produced gemsized diamonds that are harder than any other crystals, available at a rate that is up to 100 times faster than other methods used to date. The process opens up an entirely new way of producing diamond crystals for electronics, cutting tools and other industrial applications.
"This is a great example of fundamental research that will not only give us a better tool to duplicate conditions in the core of the Earth, but will stimulate many other scientific, technical and economic advances," said geologist James Whitcomb of the National Science Foundation (NSF)s division of earth sciences, which funded the research.
"We believe these results are major breakthroughs in our field," said Chih-shiue Yan, lead author of the study published in the Feb. 20, online Physica Status Solidi. "Not only were the diamonds so hard they broke the measuring equipment, we were able to grow gem-sized crystals in about a day."
The researchers developed a special high-growth rate chemical vapor deposition (CVD) process to grow crystals. They then subjected the crystals to high-pressure, high-temperature treatment to further harden the material. In the CVD process, hydrogen gases and methane gases are bombarded with charged particles, or plasma, in a chamber. The plasma prompts a complex chemical reaction that results in a "carbon rain" that falls on a seed crystal in the chamber. Once on the seed, the carbon atoms arrange themselves in the same crystalline structure as the seed. This method has been used to grow diamond crystals up to 10 millimeters across and up to 4.5 millimeters thick.
CVD-produced crystals produced very tough. "We noticed this when we tried to polish them into brilliant cuts," said Yan. "They were much harder to polish than conventional diamond crystals produced at high pressure and high temperature." The researchers then subjected the tough CVD crystals to high-temperature and high-pressure conditions. The diamonds were heated to 2000° C and put under pressures of 50,000 to 70,000 times atmospheric pressure for 10 minutes. This final process resulted in the ultra -hard material, which was at least 50 percent harder than conventional diamonds.
The research was also supported by the U.S. Department of Energy, the National Nuclear Security Agency, through the Carnegie/ DOE Alliances Center, and the W. M. Keck Foundation. It was conducted in collaboration with researchers at the Phoenix Crystal Corporation and Los Alamos National Laboratory.
Significantly more productivity in USP lasers
06.12.2016 | Fraunhofer-Institut für Lasertechnik ILT
Shape matters when light meets atom
05.12.2016 | Centre for Quantum Technologies at the National University of Singapore
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
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A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
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