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(Chem) Noble Metals

 
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adedios
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Joined: 06 Jul 2005
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Location: Angel C. de Dios

PostPosted: Thu Mar 09, 2006 7:20 am    Post subject: (Chem) Noble Metals Reply with quote






Carnegie Institution
8 March 2006
Are tougher electronic components on the way?

Materials science gets a nitride boost

Like modern day alchemists, materials scientists often turn unassuming substances into desirable ones. But instead of working metal into gold, they create strange new compounds that could make the electronic components of the future smaller, faster, and more durable. Alexander Goncharov of the Carnegie Institution's Geophysical Laboratory and colleagues* have used extreme temperatures and pressures to make two durable compounds called noble metal nitrides; they are the first to succeed in making one of them, and the first to accurately determine the chemical formula of the other. Both nitrides possess a diamond-like hardness, and some compositions might have very low, nearly superconductive electrical resistance--a blend that could prove quite valuable to industry.

The two nitrides--one containing iridium and another containing platinum--could eventually replace the titanium nitrides currently valued by the semiconductor industry as surface coatings because of their strength and durability. The researchers believe iridium and platinum nitrides might be even more durable. The group's work is presented in the March 3, 2006, issue of the journal Science.

Like several other metals such as gold, silver, and palladium, platinum and iridium are noble metals. Such metals are resistant to corrosion and oxidation, and do not easily form compounds with other elements unless coaxed to do so under very high temperatures and pressures. Goncharov and his colleagues used a special tool called a diamond anvil cell to compress the samples to nearly half a million times the atmospheric pressure at sea level. Then they used a focused laser to heat the samples to over 3000 degrees Fahrenheit, or roughly the temperature of a steel mill blast furnace. Under such extreme pressure and temperature the rules of chemistry begin to change, and noble metals can be made to form compounds with other elements such as nitrogen, as in the case of iridium and platinum nitrides.

"We are still attempting to ascertain the electronic properties of these new materials," Goncharov said. "Generally speaking, these nitrides are likely to exhibit several properties that will make them attractive for technological applications. They are potentially important for the electronics industry as durable and reliable coatings, substrates, and conductors. One can also envisage optoelectronic devices, sensitive magnetometers and other metrological equipment that employ these materials."

Though other researchers have previously made platinum nitride, Goncharov's group is the first to discover that for every platinum atom, there are two nitrogen atoms rather than just one. They are also the first to make iridium nitride, which they found has the same basic chemical formula as platinum nitride. In both cases, strong bonds that the dual nitrogen atoms make with the metal atom contribute to the nitrides' hardness and durability. The noble metals, in turn, contribute unusual electronic properties.

So far, Goncharov's group has only created small quantities of iridium and platinum nitrides in the lab. There is much work to do before these compounds can contribute to engineering and manufacturing the technology of tomorrow. But as Goncharov explains, "The present work is useful because it proves that these exotic nitrides exist, even if they were synthesized in a manner that is not practical on an industrial scale."


###
*Goncharov's collaborators include scientists from the Lawrence Livermore National Laboratory and the Atomic Weapons Establishment in England.

The Carnegie Institution of Washington (www.carnegieinstitution.org) has been a pioneering force in basic scientific research since 1902. It is a private, nonprofit organization with six research departments throughout the U.S. Carnegie scientists are leaders in plant biology, developmental biology, astronomy, materials science, global ecology, and Earth and planetary science.

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Questions to explore further this topic:

What are metals?

http://www.chem4kids.com/files/elem_metal.html
http://www.science.uwaterloo.c.....etals.html
http://www.wou.edu/las/physci/ch412/activity.htm
http://www.hometrainingtools.c.....g-tip.html

A Short History of Metals

http://neon.mems.cmu.edu/cramb.....story.html

What is an activity series?

http://antoine.frostburg.edu/c.....ries.shtml
http://www.wpbschoolhouse.btin.....tivity.htm
http://www.clickandlearn.org/activity_series.htm
http://wblrd.sk.ca/~chem30_dev.....dox2_5.htm

What are the noble metals?

http://www.diracdelta.co.uk/sc.....ource.html

Silver

http://education.jlab.org/itselemental/ele047.html
http://www.marthamine.co.nz/silver.html
http://www.ga.gov.au/education.....eruse.html
http://www.silverinstitute.org/uses.php

Gold

http://education.jlab.org/itselemental/ele079.html
http://www.marthamine.co.nz/gold_noble.html
http://www.nma.org/about_us/pu.....d_uses.asp
http://pubs.usgs.gov/gip/prospect1/goldgip.html

Platinum

http://education.jlab.org/itselemental/ele078.html
http://www.emporia.edu/earthsc.....36/dougan/
http://ist-socrates.berkeley.e.....sc/pt.html
http://r0.unctad.org/infocomm/.....m/uses.htm

Palladium

http://education.jlab.org/itselemental/ele046.html
http://www.corrosionsource.com.....dic/46.htm
http://www.stillwaterpalladium.com/uses.html

Rhodium

http://education.jlab.org/itselemental/ele045.html
http://periodic.lanl.gov/elements/45.html
http://jchemed.chem.wisc.edu/j.....elt/Rh.HTM
http://www.corrosionsource.com.....dic/45.htm

Iridium

http://education.jlab.org/itselemental/ele077.html
http://www.corrosionsource.com.....dic/77.htm
http://www.scescape.net/~woods.....idium.html

What are metal nitrides?

http://www.er.doe.gov/sub/acco.....ry/27.html
http://www.gl.ciw.edu/~hemley/.....at2004.pdf
http://webdoc.sub.gwdg.de/diss/2000/rissanen/

Besides being used in jewelry, what are the novel applications of noble metals?

http://www.nserc.ca/news/2001/win_puddephatt.htm
http://gtresearchnews.gatech.e.....tumdot.htm
http://www.cee.ucr.edu/seminars/093005.shtml
http://www.ptl.ethz.ch/research/res_top_metals
http://riskobservatory.osha.eu.....hinfo_3380
http://www.noble.matthey.com/about/index.asp
http://www.clarkson.edu/camp/reports/Suni.pdf
http://www.sud-chemie.com/scmc.....mp;lang=en
http://www.stokerconcast.com/precious-metals.html
http://www.fhi-berlin.mpg.de/t.....2-2003.pdf
http://dochowell.com/2crowns.htm

GAMES

http://www.bbc.co.uk/schools/r.....materials/
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adedios
SuperPoster


Joined: 06 Jul 2005
Posts: 5060
Location: Angel C. de Dios

PostPosted: Sat Feb 10, 2007 7:39 am    Post subject: Gold's Glittery Rewards Reply with quote

Gold's Glittery Rewards
Sarah Webb

Feb. 14, 2007

We all recognize gold, from the yellow sparkle of a chain necklace to the shiny coating on a DVD player's video and audio plugs.

Gold is a metal. It conducts electricity, and it can be shaped into sheets, long wires, or rings. Gold is an element—a substance made of one kind of atom. As an element, gold has its own square on the periodic table of chemical elements.

Gold also represents beauty and value, and it has done so for thousands of years. It's part of our culture and history.

Why do we value gold so much? It has a distinctive color. No other metal is a shiny yellow. It's also quite rare.

And this metal has other unique properties that help it keep its shine, as I learned on a recent trip to the new gold exhibit at the American Museum of Natural History in New York City.

For the full article:

http://www.sciencenewsforkids......ature1.asp
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adedios
SuperPoster


Joined: 06 Jul 2005
Posts: 5060
Location: Angel C. de Dios

PostPosted: Tue Jun 19, 2007 10:39 am    Post subject: Clue to Egypt's Gold Source Discovered Reply with quote

Clue to Egypt's Gold Source Discovered
By Dave Mosher, LiveScience Staff Writer

posted: 19 June 2007 08:46 am ET

An ancient gold-processing and panning camp has been discovered along the Nile River and is thought to be the first physical evidence of where Egypt obtained its vast gold stashes.

Aside from one gold collection site the team said was “mentioned only in passing” during the 1960s, the riverside camp about 800 miles south of Cairo is the first-known of its kind in Nubia, the region now known as northern Sudan. The archaeologists think non-Egyptians called Kushites, who ruled the region, gathered gold at the site from about 2000 B.C. to 1500 B.C. and used it to trade with Egypt.


For the full article:

http://www.livescience.com/his....._gold.html
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