| Diamond (270) |  |
| Emerald (7) | |
| Gemstone (33) | |
| Pearl (6) | |
| Sapphire (18) | |
| Spinel (71) | |
| Turquoise (5) | |
-triggered brittle failures during the olivine-spinel (mineral) phase transformation has many similar features to deep earthquakes. ang
and undergoes a transformation resulting in spinel a mineral of higher density. he research team focused on the role that phase transformations of olivine might play in triggering deep earthquakes.
and found the arthquakesonly within a narrow temperature range that simulates conditions where the real earthquakes occur in Earth. sing synchrotron X-rays to aid our observations we found that fractures nucleate at the onset of the olivine to spinel transitiongreen says. urther these fractures propagate dynamically
and avoid the segregation of Gd at the interface we have added an electronic conductor cobalt iron spinel (CFO),
Called Spinel, the material is made in a lab from synthetic powder. Under the right conditions
An added bonus to this method is that it allows the spinel to be pressed into shapes--for example, a dome for a new camera turret or a sloping panel that's flush with a wing.
spinel does it in a much lighter way. From an NRL press release about the material:
"If you replaced that with spinel, you'd reduce the weight by a factor of two
#Transparent Armor based on Spinel Could Also Ruggedize Your Smart Phone Imagine a glass window that tough like armor,
Except it not glass, it a special ceramic called spinel {spin-ELL} that the U s. Naval Research Laboratory (NRL) has been researching over the last 10 years. pinel is actually a mineral,
a thinner layer of spinel can give better performance than glass. or weight-sensitive platforms-UAVS unmanned autonomous vehicles, head-mounted face shieldst a game-changing technology.
NRL invented a new way of making transparent spinel, using a hot press, called sintering.
Sanghera says spinel has nique optical properties; not only can you see through it, but it allows infrared light to go through it.
That means the military, for imaging systems, an use spinel as the window because it allows the infrared light to come through.
NRL is also looking at spinel for the windows on lasers operating in maritime and other hostile environments. e got to worry about wave slap and saltwater and things like that,
And so that where spinel comes into its own, says Sanghera. Says Sanghera, verything we do,
What is spinel? Spinel can be mined as a gemstone; a famous example is the Black Prince Ruby,
which is actually spinel with a color dopant. NRL chemists have synthesized also their own ultra-high purity spinel powder,
and other synthetic versions are commercially available. he precursors are all earth abundant, so it available in reasonably low cost, says Sanghera.
The spinel NRL makes is a polycrystalline material, or a lot of crystal particles all pressed together.
Whereas with glass, crack that forms on the surface will go all the way through, spinel might chip
but it won crack. t like navigating through the asteroid belt, you create a tortuous path:
When scientists first started trying to make glass-like spinel, they were using a crucible instead of a press. big problem with growing crystals is that you have to melt the starting powder at very high temperatures,
the spinel will come out flat. ut if I have a ball and socket joint, put the powder in there,
with the sintering aid they were adding to the spinel powder. t about one percent of a different powder,
and the spinel will come out clear across the press. To further increase the quality of the optic, ou can grind
The military in particular may want to use spinel as transparent armor for vehicles and face shields.
and glass perhaps five inches thick. f you replaced that with spinel, you reduce the weight by a factor of two or more,
The military also interested in using spinel to better protect visible and infrared cameras on planes and other platforms.
Spinel windows could also protect sensors on space satellites, an area Sanghera interested in testing. ou could leave these out there for longer periods of time,
NRL is also looking at spinel (and other materials) for next generation (NEXTGEN) lasers. asers can be thought of as a box comprised of optics,
working with ltra high purityspinel powder theye synthesized in NRL clean rooms, spinel incredible potential. For active laser applications, theye demonstrated how sintering can be used with materials other than spinel to make a laser that xcellent optical quality.
Instead of spinel they use, hings like yttria or lutecia and and dope them with rare earth ions.
NRL has transitioned both types of laser materials and applications to industry. What makes NRL tick is solving problems Sanghera came to NRL in 1988,
and a lot of his success with spinel comes from that heritage of insisting on purity and quality. n optical fiber very long:
To meet that need scientists at the U s. Naval Research Laboratory (NRL) have developed a method to fabricate nanocrystalline spinel that is 50%harder than the current spinel armor materials used in military vehicles.
With the highest reported hardness for spinel NRL's nanocrystalline spinel demonstrates that the hardness of transparent ceramics can be increased simply by reducing the grain size to 28 nanometers.
This harder spinel offers the potential for better armor windows in military vehicles which would give personnel and equipment such as sensors improved protection along with other benefits.
To create the harder spinel the NRL research team sinters or consolidates commercial nanopowders into fully dense nanocrystalline materials.
However the NRL team is the first to succeed in making this harder spinel through their development of the Enhanced High pressure Sintering (EHPS) approach explains Dr. James Wollmershauser a lead investigator in the research.
Using this EHPS approach to create the nanocrystalline spinel the NRL research team did not observe any decline in density or fracture resistance due to residual porosity.
Other researchers have tried to make nanocrystalline spinel but they have had all problems with the final product such as a reduced density reduced fracture resistance or reduced transparency.
In current applications spinel and sapphire (which is also very hard) are used to create materials for military armor windows.
By increasing the hardness of spinel even further NRL researchers can make a material harder than sapphire
and possibly replace sapphire windows with windows made out of nanocrystalline spinel. Also harder nanocrystalline spinel windows can be made thinner and still meet the current military specifications.
This thinness translates to weight savings on the vehicle. So the NRL-developed nanocrystalline spinel brings improvements in hardness window thickness and weight and cost.
A final benefit is that the NRL-developed nanocrystalline spinel is highly transparent making it useful in UV visible and infrared optics.
The armor material used by the military needs to be transparent so that both equipment and personnel can see.
A single window that could be produced using the NRL-developed nanocrystalline spinel would be transparent across many technologically important wavelengths easing design
Beyond the use for a harder spinel in armor windows there could be other potential Dod and civilian applications in better/stronger office windows smartphones and tablets screens military/civilian vehicles
in addition to SPGM#DOC and Spinel, #which we plan to employ in our own catalyst coatings
including Spinel, #with more interim results soon to be announced
#Mild Carbonization Process Converts Polymer Organic Frameworks into Nanometer-Thick Carbon Sheets"We have developed a'designer carbon'that is both versatile and controllable,
HZB team decodes relationship between magnetic interactions and the distortions in crystal structure within a geometrically'frustrated'spinel system Abstract:
A team at HZB has carried out the first detailed study of how magnetic and geometric ordering mutually influence one another in crystalline samples of spinel.
The results were published in Physical Review B. Spinels consist of densely packed, highly symmetrical planes of oxygen atoms (somewhat like a densely packed box of marbles) where different metallic elements are lodged in the spaces between them.
The embedded metal ions in the Ni1-xcuxcr2o4 spinel system cause a distortion of the crystal structure.
The HZB team has analysed now comprehensively the chromium-spinel system and have explained the complex phase diagram at a fundamental level for the first time.
The series begins with samples of pure nickel-chromium spinel (x=0; a green powder) and continues with increasing proportions of copper.
which lies far below room temperature for pure nickel-spinel as well as for copper-spinel.""We were able for the first time to determine the magnetic characteristics exactly
Peninsula of orthorhombic state At a mixture ratio of 85%nickel and 15%copper, the spinel system displays a kind of narrow peninsula of orthorhombic state in the phase diagram where the observed Anm
New insight into the fundamentals of solid state physics A team at HZB has carried out the first detailed study of how magnetic and geometric ordering mutually influence one another in crystalline samples of spinel.
The results were published in Physical Review B. Spinels consist of densely packed highly symmetrical planes of oxygen atoms (somewhat like a densely packed box of marbles) where different metallic elements are lodged in the spaces between them.
The embedded metal ions in the Ni1-xcuxcr2o4 spinel system cause a distortion of the crystal structure.
The HZB team has analysed now comprehensively the chromium-spinel system and have explained the complex phase diagram at a fundamental level for the first time.
The series begins with samples of pure nickel-chromium spinel (x=0; a green powder) and continues with increasing proportions of copper.
which lies far below room temperature for pure nickel-spinel as well as for copper-spinel.""We were able for the first time to determine the magnetic characteristics exactly
Peninsula of orthorhombic state At a mixture ratio of 85%nickel and 15%copper, the spinel system displays a kind of narrow peninsula of orthorhombic state in the phase diagram where the observed Anm
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