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New Material Harder Than Diamond
h4x0r-3l337 writes "Diamond is no longer the hardest substance known to man. Scientists have created a new material, called "aggregated diamond nanorods" by compressing carbon-60 under high heat. From the article: 'The hardness of a material is measured by its isothermal bulk modulus. Aggregated diamond nanorods have a modulus of 491 gigapascals (GPa), compared with 442 GPa for conventional diamond.'"
Long time ago, when I was student, I bought a very good russian thermodynamics book (Kirillin) where they said Borazon synthetic material be harder than diamond. It is a pity Wikipedia does not agree with that fact.
Of course, the thermodynamic process to achieve it was far expensive. Required very high pressure and temperatures.
To be honest, I'm not sure those tests would work...
The hardest scale on the Rockwell test (I'll let someone else give a link somewhere) uses a diamond to make an indent. This works for pretty much everything since diamond is the hardest material.
Until now, at least. Since diamond isn't harder than this, it wouldn't make an indent. No indent, no Rockwell reading.
"Most (if not all) of the diamond in diamond coated drills are produced through this process"
You were OK, sortof. It's not the GE process, but something entirely new (relatively).
Diamond coatings are done through a process called Vapor Deposition. It's a low pressure process, done at Standard Pressure, using a hot carbon rich gas, a reducing atmosphere, and a cold substrate (the thing you're coating).
It's an entirely new process, discovered entirely by accident by someone trying to figure out why certain welds were a bitch to grind smooth. It turned out that there were microscopic diamonds in the welds, and that was why.
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BMO
Carbon is the most electronegative element with a valence of 4. Electronegativity increases on the periodic table going right and up, and it is a measure of how strongly an atom holds onto electrons. This means that carbon can form four extremely strong atomic bonds with other carbon atoms. Because the bonds are strong, they will make a structure extremely hard if the bonds are arranged into inflexible shapes. Repeating triangles make diamond. Hexagons and Pentagons folding back on each other make buckminsterfullerene (buckyballs). Hexagons rolled into cylinders make nanotubes. The fact that it can make 4 bonds allows all these repeating shapes (polymers) to come about.
Carbon is the only element that has these properties (valence 4, high electronegativity) that allow it to form the structures it does. Under extreme pressure and temperature, it's believed that silicon could be coaxed into some kind of polymerization. I remember reading once that a research group managed to polymerize pure nitrogen under megabars of pressure and thousands of degrees F. The result had 3 times the energy density of TNT, and violently decomposed when the pressure was let off - can anyone elaborate or corroborate?
Anyway, hope this helps!
The group created the ADNRs by compressing the carbon-60 molecules to 20 GPa, which is nearly 200 times atmospheric pressure
200 atmospheres? That's not much pressure. SCUBA divers regularly put more pressure than that in tanks they wear strapped to their backs.
According to the "units" program on my laptop, 20 GPa is 197,384.65 atmospheres. 200 *thousand* atomospheres... that makes more sense.
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Yes.
Clearly, they are the same.
I often try to pick up girls by handing them large chunks of coal since it's a diamond, but in a different state. For some reason, they don't seem to go for it. Odd.
Strangely enough, no one will eat my burgers cooked over graphite (and quite frankly, graphite fires are a bit difficult to keep lit).
Carbon is one of the most versitile elements on the planet either alone or combined with other elements. Its quite worthwhile to consider a different state of it a completely different thing.
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