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Scientists create matter that can dent diamonds

phys.org

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Re: Scientists create matter that can dent diamonds

#11
Diamond is only the hardest known naturally occurring material.

For the hardest known material, take a look at this paper from 2005: http://adsabs.harvard.edu/abs/2005ApPhL..87h3106D

Or the Wikipedia article for a more general treatment: https://en.wikipedia.org/wiki/Aggregated_diamond_nanorod

Re: Scientists create matter that can dent diamonds

#12
post #11

Diamond is only the hardest known naturally occurring material. For the hardest known material, take a look at this paper from 2005: http://adsabs.harvard.edu/abs/2005ApPhL..87h3106D Or the Wikipedia article for a more general treatment: https://en.wikipedia.org/wiki/Aggregated_diamond_nanorod

Not even that, quite. There are two known naturally occurring minerals that are harder than diamond: wurtzite boron nitride, and lonsdaleite (another carbon allotrope). They just don't occur in very large quantities.

Ref: http://www.newscientist.com/article/dn16610-diamond-no-longe...

Re: Scientists create matter that can dent diamonds

#13

Let's see what the actual journal article says. http://www.sciencemag.org/content/337/6096/825.abstract?sid=... Long-Range Ordered Carbon Clusters: A Crystalline Material with Amorphous Building Blocks Lin Wang, Bingbing Liu, Hui Li, Wenge Yang, Yang Ding, Stanislav V. Sinogeikin, Yue Meng, Zhenxian Liu, Xiao Cheng Zeng, and Wendy L. Mao Science 17 August 2012: 337 (6096), 825-828. [DOI:10.1126/science.1220522] The S…

Materials Scientist here.

There are no small-scale diamonds present in the material. On the small scale, the material is a carbon glass (an unordered, or amorphous solid), distinct from diamond, which is an ordered crystal. Typically, high density glasses are stronger than crystals made from the same elements, so the strength of the material isn't particularly surprising, rather it's the processing of the new material that is novel.

It's also worth noting that this isn't even the first carbon-based material stronger than diamond. Lonsdaleite is a closely related structure that is significantly stronger. It is much less common, however, naturally occurring only in meteorites.

Re: Scientists create matter that can dent diamonds

#15
post #13

Let's see what the actual journal article says. http://www.sciencemag.org/content/337/6096/825.abstract?sid=... Long-Range Ordered Carbon Clusters: A Crystalline Material with Amorphous Building Blocks Lin Wang, Bingbing Liu, Hui Li, Wenge Yang, Yang Ding, Stanislav V. Sinogeikin, Yue Meng, Zhenxian Liu, Xiao Cheng Zeng, and Wendy L. Mao Science 17 August 2012: 337 (6096), 825-828. [DOI:10.1126/science.1220522] The S…

Materials Scientist here. There are no small-scale diamonds present in the material. On the small scale, the material is a carbon glass (an unordered, or amorphous solid), distinct from diamond, which is an ordered crystal. Typically, high density glasses are stronger than crystals made from the same elements, so the strength of the material isn't particularly surprising, rather it's the processing of the new materia…

Any idea as to which one is actually harder, the new material, or Lonsdaleite? I see from this journal that Lonsdaleite has 58% higher indentation strength than diamond: http://prl.aps.org/abstract/PRL/v102/i5/e055503 but I couldn't find figures for the new material.
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