Now, ultra-hard graphite that can crack diamonds!
By ANISunday, November 7, 2010
LONDON - Scientists have shown that when compressed, graphite can crack a diamond.
Now computer simulations by Hui-Tian Wang at Nankai University in Tianjin, China, and colleagues have shown that the compressed material could be at least partly made of bct-carbon, which is built up from rings of four carbon atoms, reports New Scientist.
Bct-carbon has attributes of both diamond, which has a cubic structure, and graphite, composed of loosely linked sheets of carbon atoms in a hexagonal lattice. In bct-carbon, layers of carbon rings are linked by strong vertical bonds.
Wang’s team reckons that bct-carbon’s shear strength - a measure of how difficult it is to slide the carbon layers over one another - is 17 per cent greater than that of diamond.
The results indicate the prospect of making exceptionally hard materials without extreme heating. Most other materials we suspect to be harder than diamond require both high temperature and pressure to form.
Artem Oganov at the State University of New York in Stony Brook said that, compared with other candidates, there is “a much stronger basis” for bct-carbon to be harder than diamond, but added that experiments are still needed to test the claims. (ANI)
