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posted by Fnord666 on Sunday March 19 2017, @11:39AM   Printer-friendly
from the seeing-is-believing dept.

DESY, the Deutsches Elektronen-Synchrotron research center, has created a transparent, extremely hard ceramic.

Scientists have synthesised the first transparent sample of a popular industrial ceramic at DESY. The result is a super-hard window made of cubic silicon nitride that can potentially be used under extreme conditions like in engines, as the Japanese-German team writes in the journal Scientific Reports. Cubic silicon nitride (c-Si3N4) forms under high pressure and is the second hardest transparent nanoceramic after diamond but can withstand substantially higher temperatures.

"Silicon nitride is a very popular ceramic in industry," explains lead author Dr. Norimasa Nishiyama from DESY who now is an associate professor at Tokyo Institute of Technology. "It is mainly used for ball bearings, cutting tools and engine parts in automotive and aircraft industry." The ceramic is extremely stable, because the silicon nitrogen bond is very strong. At ambient pressures, silicon nitride has a hexagonal crystal structure and sintered ceramic of this phase is opaque. Sintering is the process of forming macroscopic structures from grain material using heat and pressure. The technique is widely used in industry for a broad range of products from ceramic bearings to artificial teeth.

At pressures above 130 thousand times the atmospheric pressure, silicon nitride transforms into a crystal structure with cubic symmetry that experts call spinel-type in reference to the structure of a popular gemstone. Artificial spinel (MgAl2O4) is widely used as transparent ceramic in industry. "The cubic phase of silicon nitride was first synthesised by a research group at Technical University of Darmstadt in 1999, but knowledge of this material is very limited," says Nishiyama. His team used a large volume press (LVP) at DESY to expose hexagonal silicon nitride to high pressures and temperatures. At approximately 156 thousand times the atmospheric pressure (15.6 gigapascals) and a temperature of 1800 degrees Celsius a transparent piece of cubic silicon nitride formed with a diameter of about two millimetres. "It is the first transparent sample of this material," emphasises Nishiyama.

It's no transparent aluminum, but it'll do.


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  • (Score: -1, Offtopic) by Anonymous Coward on Monday March 20 2017, @01:29AM

    by Anonymous Coward on Monday March 20 2017, @01:29AM (#481312)

    In reviewing the week, CounterPunch editor Jeffrey St. Clair noted [counterpunch.org]

    The most edifying takeaway from Trump’s big interview with Tucker Carlson on FoxNews this week concerned his reading habits, which weigh-in at about half-a-Palin. Of course, he’d read a little more, if he didn’t have to spend all day making America tremendously great again:

    Tucker Carlson: What do you do at the end of the day? What do you read, what do you watch...

    Donald Trump: Well, you know, I love to read. Actually, I’m looking at a book, I’m reading a book, I’m trying to get started. Every time I do about half a page, I get a phone call that there’s some emergency, this or that. But we’re going to see the home of Andrew Jackson today in Tennessee and I’m reading a book on Andrew Jackson. I love to read. I don’t get to read very much, Tucker, because I’m working very hard on lots of different things, including getting costs down. The costs of managing our country are out of control. But we have a lot of great things happening, we have a lot of tremendous things happening.

    -- OriginalOwner_ [soylentnews.org]

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