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February 25, 2008
ADT announces revolutionary family of diamond pump seals.
Click here to see the full announcement.
February 4, 2008
DOE features ADT in a case
study on Energy Efficient Technologies.
January 26, 2008
Mechanical seal performance improvement after UNCD is featured in the cover
story, "Reliability Galore - Diamonds Are For Seal Faces" in the January
2008 issue of
Maintenance Technology.
December 26, 2007
ADT Co-founder Orlando Auciello interviewed
for CNN's Situation Room regarding UNCD's role as a potential base in a bioterrorism detection system.
December 20, 2007
"Are
Diamonds a MEMS' Best Friend?" article featured in IEEE microwave magazine's
December 2007 issue explains how UNCD is poised to play a powerful role in the
future of RF MEMS.
See more news items...
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Technical Description |
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| Image Caption |
UNCD®, motivated by the Ultrananocrystalline Diamond material originally developed
at Argonne National Laboratory, has been extended by ADT to a family
of diamond materials which finally enables diamond as a true engineering
material.
A key characteristic of all UNCD films is their phase purity.
None of the UNCD films consists of a mixture of diamond and graphitic
phases although UNCD Aqua 25 has volume fractions of grain
boundaries that amount to 10% of the film by volume and consist
of carbon in several different bonding states including sp2
(graphitic). UNCD films are not diamond-like carbons or "NCD"
(for nanocrystalline diamond) films reported in the literature.
It is this unique structural property of UNCD films that allows
attributes such as optical transparency, electrical and thermal
conductivity, and film stress to be controlled in ways not possible
with other materials.
ADT’s techniques also allow the structure-properties of UNCD to
be tuned. This is done by changing the growth process to increase
the grain size and to introduce select impurities (dopants like
boron, nitrogen, etc.) to engineer UNCD's electrical, thermal and
optical properties. Although the typical growth temperatures are
700-800 °C, UNCD films can be deposited at much lower temperatures
down to 350 °C. UNCD can be grown on a wide variety of substrates,
including Si, SiO2 (thin
oxide films, quartz, Corning glass), refractory metals (Ti, Ta,
W, Mo), as well as SiC and SiN. Continuous films can be grown to
render the substrate impervious to chemical attack from strong acid
solutions such as HF and HNO3.
Thanks to recent advances in deposition technology, UNCD films can
be routinely deposited onto silicon wafers up to 200 mm in size.
Below are some of the material properties of UNCD that enable its
unique characteristics.
- Mechanical Properties. Most UNCD films are essentially
equivalent to natural diamond in hardness, Young’s modulus,
fracture toughness and strength.
- Tribological Properties. When smooth, UNCD exhibits
friction coefficients as low as 0.03 in air. This, combined
with the extreme hardness and good adhesion properties, allows
for a wide range of applications of UNCD as a tribomechanical
coating.
- Transport Properties. By altering the deposition
process, the electrical conductivity of UNCD films can be changed
over eight orders of magnitude. UNCD Brown films exhibit the
highest N-type conductivity reported for a phase-pure diamond
film and are more conductive than any doped microcrystalline
diamond film or diamond-like carbon film.
- Electron Field Emission Properties. UNCD films
consistently exhibit very low threshold fields for field electron
emission. In addition, the field electron emission is
very stable even when the surface is exposed to 10-4
Torr of oxygen or hydrogen. Emission currents as high
as 100 µA from a single UNCD-coated silicon microtip have been
observed. Emission currents as high as 1 mA have been
achieved from conformally-coated arrays of silicon microtips.
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Copyright 2004-2008. Advanced Diamond Technologies, Inc.
429 B Weber Road #286, Romeoville, IL 60446. Phone: 815-293-0900
UNCD is a registered trademark of; NaDiaProbe, DoSi, DOI, We Solve Hard Problems,
We Haven't Even Scratched the Surface, Diamond is an Engineering Material and
the ADT logo are trademarks of Advanced Diamond Technologies, Inc.
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