Version 6 Asha Simulated Diamond Testing:
Test 1: Raman spectroscopy by
Evans Analytical
Group
Excerpted from
Report:
Purpose:
To detect the presence of a diamond
like carbon (DLC) coating on a zirconia gem.
Summary:
DLC was detected by Raman spectroscopy
on the gem coating. The DLC was of high quality, having
probably up to 85% sp3 content, typical for a tetrahedral
amorphous carbon.
Experimental:
The
Raman measurements were performed with a �Dilor� J-Y
spectrometer (�LabRam�) equipped with a �BX40 Olympus�
microscope using the backscattering geometry (1800). A HeNe
laser (632.8 nm wavelength) and a 600 gr/mm grating were
used in these measurements, which were repeated with an Ar+
ion laser (514.5 nm wavelength) and an 1800 gr/mm grating.
The full report is available
in PDF format for viewing here:
http://betterthandiamond.com/reports/EvansAnalytical_raman.pdf
Notes: The
sample submitted was an H/I color.
Gemologist
with access to Raman who would like to independently
reproduce this testing should feel free to
contact us to arrange for test samples with various
thickness of amorphous diamond coating (color set) as
differing Raman systems have varying sensitivity.
Version 5 testing:
We have sent
our Asha version 5 to three different independent testing
labs to show the results of our amorphous diamond infusion
process. We are pleased to show the results below:
The three
tests run were:
1)X-Ray Photoelectron Spectroscopy (XPS).
2)Contact Angle Goniometry
3)Raman microspectroscopy
Test
1: X-Ray Photoelectron Spectroscopy (XPS)
Purpose: To verify the
elemental (surface) composition of the Asha Diamond Simulant
Results: "The
principal element found at the surface is carbon".
Summary:
The principal
element found at the surface is carbon. As would be
expected, considerable surface oxygen was also measured.
An atomic concentration of zirconium of 3.1 atomic % was
found in the surface of the coating
[note: they indicated that during the coating/infusion
process, some of the zirconium is being knocked into the
mix].
The elemental concentrations in atomic % of the surface of
the DLC coated Asha diamond simulant after the removal of
surface debris with ultrasonic cleaning are:
| Elements |
Asha
Diamond Simulant Surface |
| C
(Carbon) |
77.07% |
| O
(Oxygen) |
17.09% |
| Zr
(Zirconium) |
3.14% |
At concentrations below 1
atomic % N(0.71%), Y(0.61%), Si(0.53%), F(0.42%), Cl(0.31%),
and Mg(0.11%) were detected in the coating.
Nomarski contrast image
(tinted) of the Asha surface
taken prior to XPS testing
Test performed by: Anderson
Materials Evaluation Laboratories (April, 2007)
Equipment used: "The
surface of the coated Asha diamond simulant after ultrasonic
cleaning was examined with XPS using a monochromatic
aluminum X-ray source. The quantitative elemental
concentration results were obtained from elemental survey
spectra covering the binding energy range from 0 to 1100 eV
with a step size of 0.5 eV and long 4 hour data acquisition
time for improved accuracy".
Test
2: Contact angle goniometry
Purpose: To 'visually' show the
amorphous diamond coating
Results: The Asha
(version 5) with coating showed roughly 300% difference in contact angle
as compared to an uncoated Asha core.
[Note: we have
long known that the amorphous diamond coating helps keeps
the Asha much cleaner, much longer than uncoated Asha or
plain CZ as it has a coefficient of friction lower than
teflon - this test helps show that effect.]
Uncoated
Asha, polished core - contact angle of 98.5 degrees:
Asha
with amorphous diamond coating - contact angle of
31.7 degrees:
Test
performed by: Future
Digital Scientific Laboratories (March, 2007)
[Of interest,
contact angle testing has been used to id authentic
historical coins vs. otherwise undetectable fakes...because
water contains billions of hydrogen atoms, it is very
interactive and thus differing material surfaces will show
varying contact angles even when other tests do not detect a
difference.]
Test
3: Raman microspectroscopy
Purpose: To verify Asha
contains diamond content
Results: The Asha
(version 5) shows a diamond signature when run under Raman.
Test performed by: Intertek
Northwest, NWTC Lab, England (July, 2004)
Equipment used: Confocal raman microscope with 785nm
diode laser excitation
Comments:
As you can see
above, both the Asha and natural diamond exhibit a strong
spike at nearly the same frequency - this is because both
contain SP3 carbon (diamond bonds), and this spike is
something no other diamond simulant can show, because no
other diamond simulant has this level of diamond bonds
integrated into its composition.
Raman testing is frequently done as a standard way to
identify the composition of various gemstones, both natural
and man-made, as it is relatively cheap to do, and is
completely non-destructive. The Asha
diamond simulant is the only diamond simulant in the world
that employs a form of amorphous diamond pure enough to
easily register under standard Raman microspectroscopy.
This is why we note that Asha is the diamond worlds
equivalent of the cultured pearl, because just as a pearl
has an outer layer of nacre, the Asha employs an outer layer
of amorphous man-made diamond.
