of the problem.
Further, the concept of para-crystallinity also includes materials which are
not well-behaved and 3-dimensionally ordered substances. This is
well-recognized in high polymer systems, but it also occurs in organic and
inorganic materials. How does one assess the crystallinity
.
The business about getting a standard with a known crystallinity is an
issue, but not as unsurmountable as it seems. Firstly SRM676 and
SRM676a have certified crystallinity values with errors of +-1%. Given
the likely errors in subsequent lab determinations is quite large this
isn't as much
to determine the percentage crystallinity in a
crystalline/amorphous mixture, could someone point me in a foolproof
direction.
Thanks,
John
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James P. Cline
Ceramics
Division
National Institute of Standards and Technology
100 Bureau Dr
John ( others),
The best way to determine %crystallinity (or %amorphous) is to do spiking
experiments with material with known (preferably ~100%) crystallinity. The
change in the apparent phase fractions by Bragg intensities as compared to that
expected from the masses can be used to estimate
Determination of crystallinity can be a fraught subject, because it is
usually assumed in such measurements that the background is from
amorphous material while the sharp peaks are from crystalline material.
So the standard way to do this would be to have a method for extracting
the background
Regarding Crystallinity -
As a technicality, the concept of % crystallinity is not only an x-ray
analysis issue. One can measure % crystallinity by other methods - and the
findings (numbers) from the different techniques are not necessarily the same.
I'm not sure if there is a technique
it isn't and good
sample preparation is vital.
Pam
From: Von Dreele, Robert B. [mailto:[EMAIL PROTECTED]
Sent: Wed 27/02/2008 11:52 AM
To: rietveld_l@ill.fr
Subject: RE: % Crystallinity
John ( others),
The best way to determine %crystallinity (or %amorphous
if
something is precisely 100 or 50 or another amount. In order to do that,
one must have a standardwhich is circular logicand which illustrates at
least part of the problem.
Further, the concept of para-crystallinity also includes materials which are
not well-behaved and 3
Dear All,
I would like to know the procedure to estimate the crystallinity from
powder XRD data for nanomaterials with different crystallite size. I found in
literature about Debye Function Analysis (DFA) for generating the powder
pattern for nanoparticles with different size containing
