炭素の第３相と考えられるQカーボンはダイヤモンド構造をしていないの？レーザーで200nsで３７００℃まで熱して急冷するという。通常のダイヤモンドは正四面体のｓｐ３構造であるが（７５～８５％）Qダイヤモンドはｓｐ２構造が含まれるｔｐしている。
ダイヤモンドしのぐ硬さと輝き 米大学が新物質を開発
CNN.co.jp 12月3日(木)15時13分配信 headlines.yahoo.co.jp
（ＣＮＮ） 米ノースカロライナ州立大学の研究チームはこのほど、ダイヤモンドより明るく輝き、しかも硬度が高い新物質を開発したと発表した。
応用物理学専門誌「ジャーナル・オブ・アプライド・フィジクス」の最新号に発表された論文によると、新たな物質の名前は「Ｑカーボン」。
炭素原子に瞬間的にレーザーを当てて超高温まで熱し、その後急速に冷やすという方法で作ることができる。
レーザーを照射する時間は２００ナノセカンド。１ナノセカンドは１秒の１０億分の１を示す単位だ。
熱した炭素の温度は約３７００度と、地球内部で天然ダイヤモンドが生成された時の高温状態をはるかに上回る。
チームによると、こうして作られた物質はダイヤモンドと同じく炭素原子で構成される固体だが、これまで地球上に存在したことはないとみられる。
論文の執筆を率いたノースカロライナ州立大学のジェイ・ナラヤン氏は
「自然界に存在するとすれば、どこかの惑星の中心核しか考えられない」
と話す。
鉛筆の芯に使われる黒鉛もやはり純粋な炭素でできた物質だが、ダイヤモンドとは結晶構造が違う。ダイヤモンドは炭素原子同士が非常に強く結びついているため、最も硬い天然物とされてきた。透明性や美しい輝きも大きな特徴だ。
ところがチームによると、Ｑカーボンはダイヤモンドよりもさらに硬いだけでなく、少ない光で一層強い輝きを放つ。さらに磁気を帯びさせることもできることから、さまざまな分野での応用が期待される。
ナラヤン氏によると、人工ダイヤの一種、ナノダイヤモンドを使った医療用の針や膜を低コストで作ったり、がんの治療薬を体内の患部に届ける技術に役立てたりする活用法も考えられる。
チームは今後、Ｑカーボンの性質などについて、さらに詳しく調べていく構えだ。
Diamonds, move over: Scientists make harder, brighter Q-carbon
By Ben Brumfield, CNN
(CNN)—Scientists have created a substance that blings even brighter than diamonds, but chances are you won't wear it. You'll take its byproducts as medicine instead.
It's called Q-carbon, and researchers at North Carolina State University have made it by zapping a kind of loose carbon with a laser beam that lasts a fraction of a fraction of a blink of an eye -- 200 nanoseconds.
That's only 200 billionths of a second, but it's enough to heat the carbon to about 3,700 degrees Celsius. That's not far from double the heat many scientist say it took to make natural diamonds when they were formed a billion or more years ago.
Then the researchers let that carbon cool immediately, snapping its atoms into a special crystalline structure.
.
The result is a new substance that may have never existed on Earth before and has some unique properties.
The researchers published their results in the Journal of Applied Physics.
About that carbon
Carbon gets a lot of bad rap these days as a culprit of global warming. But that's mostly carbon dioxide -- carbon joined in a molecule with oxygen.
In its pure form, carbon is something very different altogether. It only exists in a few solid forms, which contrast sharply from one another because of how they are put together.
Got a pencil? Look at the "lead." It's not lead; it's graphite, which is a solid form of pure carbon, a very common one.
When you're writing, you can see how soft it is as it comes off onto the paper with ease.
Then there's the rare stuff, the bling -- diamonds. Same carbon, very different crystalline structure. It's a lot tighter and smaller, which makes it the hardest naturally occurring substance on Earth, according to the University of Illinois at Urbana-Champaign.
Graphite is also gray and smudgy, and diamonds have pretty unbeatable clarity and bling.
Q-carbon has an even stronger brilliance, glowing even in the lowest light, the researchers said. But it's not diamond, and it's not graphite.
A brand new thing
It's its own thing, which means that scientists have created a new form of solid carbon that probably otherwise does not exist on Earth.
"We've now created a third solid phase of carbon,"
said N.C. State researcher Jay Narayan and lead author of three papers on the innovation.
"The only place it may be found in the natural world would be possibly in the core of some planets."
And it has some properties that make it different from diamonds. It's even harder. But the clincher -- it's ferromagnetic. That means it can be magnetized.
Its intense glow could make electronic displays brighter and clearer.
Take your diamonds
Engineers can also vary the laser blast to create diamond structures in the Q-carbon, and that's where the medical possibilities come in.
"We can create diamond nanoneedles or microneedles, nanodots or large-area diamond films, with applications for drug delivery,"
Narayan said. And they could be made cheaply.
Nanodiamonds are on the cutting edge of cancer drug research. They are nontoxic, says Drexel University, which is researching their use to deliver anti-cancer drugs into brain tumors.
N
anodiamonds are nothing new, so why use this new stuff to make them instead of using it directly instead?
FIG. 1.
(a) Carbon phase diagram (P vs. T) following Bundy et al.1 that has amorphous diamond-like carbon melting at 4000 K at ambient pressures (dotted green line) and
(a) Carbon phase diagram (P vs. T) following Bundy et al.1 that has amorphous diamond-like carbon melting at 4000 K at ambient pressures (dotted green line) and
(b) phase diagram at lower pressures and temperatures.