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| 2004/2/25-26 [Politics/Foreign/MiddleEast/Iraq] UID:12404 Activity:nil |
2/24 Is this the end of DeBeers?
http://www.eurekalert.org/pub_releases/2004-02/ci-ldm022504.php
\_ wasn't this in Wired like 3 months ago?
\_ DeBeers has been aware of the threat of synthetic diamonds for a
while now. They've responded by putting micro-etching on the rim
of natural diamonds gauranteeing their origin. They also started a
PR program to convince people that synthetic diamonds are like
cheating by buying a cubic zirconia and that if you really love your
woman you'll get her a 'real' diamond. They have also started a
program to help jewelers tell the difference between natural and
synthetic diamonds, mainly that synthetics are 'too perfect'.
The manufacturers fight back by calling them 'created diamonds' to
emphasize the craftsmenship and the fact that they were not dug out
of mud by people working for peanuts to finance some civil war.
One other thing is large synthetic diamonds, if cut into flat pieces
would make an excellent substrate for microprocessors.
\_ "some civil war" and slavery and the drug trade, too.
\_ It's true that diamond would make a nice material for
microprocessors, but there's a lot of materials black magic
that has to happen to make a current CPU. It's not clear
how hard it'll be to replicate all the black magic on diamond.
\_ Synthetic diamond is not quite up to the par just yet. The
gem-quailty diamond has a natual yellow tint. The funny thing is
that in the past, natural yellow-diamond cost a bundle. Until
these guys managed to make gem-quality CLEAR-colored diamond,
DeBeer is not really being threaten.
--one who hate DeBeer more than Microsoft.
\_ they can manufactur clear colored diamonds. they however
found that they can make the yellow ones faster and charge
about the same, so they focus the manufacturing on yellow
diamonds. also, debeers wont come after them quite so fast
for now. you should read the Wired article, it explains this
very well.
\_ Neither synthetic nor natural diamonds have to have a yellow
tint. There is no 'natural' diamond color, although some
colors are more frequent than others. Clear and yellow
(various shades) are most common, blue and red (I think) are
the rarest. The price tends to rise with rarity of color.
-- ilyas
\_ The colors come from impurities (non-diamond minerals). |
| www.eurekalert.org/pub_releases/2004-02/ci-ldm022504.php Further, the researchers grew these diamonds directly from a gas mixture at a rate that is up to 100 times faster than other methods used to date. We believe these results are major breakthroughs in our field, said Chih-shiue Yan, lead author of the study published in the February 20, online Physica Status Solidi. Not only were the diamonds so hard that they broke the measuring equipment, we were able to grow gem-sized crystals in about a day. The researches grew the crystals using a special high-growth rate chemical vapor deposition CVD process that they developed. They then subjected the crystals to high-pressure, high-temperature treatment to further harden the material. In the CVD process, hydrogen gas and methane are bombarded with charged particles, or plasma, in a chamber. The plasma prompts a complex chemical reaction that results in a carbon rain that falls on a seed crystal in the chamber. Once on the seed, the carbon atoms arrange themselves in the same crystalline structure as the seed. They have grown single crystals of diamonds up to 10 millimeters across and up to 45 millimeters in thickness by this method. We noticed this when we tried to polish them into brilliant cuts, said Yan. They were much harder to polish than conventional diamond crystals produced at high pressure and high temperature. The researchers then subjected the tough CVD crystals to high-temperature and high-pressure conditions. The diamonds were heated to 2000 C and put under pressures between 50,000 and 70,000 times atmospheric pressure 5-7 GPa for ten minutes. This final process resulted in the ultrahard material, which was at least 50 harder than the conventional diamonds as shown by direct measurements carried out in collaboration with scientists at Los Alamos National Laboratory. Making diamonds has not been the primary goal of our research, remarked Russell Hemley of Carnegie. Our group is interested in the behavior of materials at extreme pressures and temperatures. We need large, perfect diamond crystals to create new classes of high-pressure devices for our research and decided to explore whether we could make these crystals by CVD processes. This has opened up an entirely new way of producing diamond crystals for a variety of applications, such as the next generation diamond-based electronics devices and cutting tools. Our new finding that the diamonds can be supertough and/or superhard was a surprise and will greatly benefit many of these applications. |