On Wed, 19 May 1999, Natale Perchiazzi wrote:
> Dear All,
>
> I am planning to do crystallite size determinations and I think that a
> reasonable way to begin may be to analyze well known materials, so to verify
> what is working properly (and what not....).
>
> As the SRM 674a set of oxides (namely corundum, cerianite, rutile, chromite)
> is available in our laboratory, I would ask what values were determined for
> the crystallite size of these standard materials. Any hint or suggestion
> warmly welcome.
>
Dear Natale Perchiazzi,
in Feb/Mar 1999, we have investigated two of this oxides for
size/microstrain. Our results were published as a poster named
"Standardfreie Size/Strain-Bestimmung mit dem Rietveld-Programm BGMN"
(standardfree size/strain estimation using the Rietveld program BGMN)
at the annual conference of the DGK (german crystallographers association)
in Leipzig. The news on this poster was the tube tails correction,
see
http://www.bgmn.de/tubetails.html
We have investigated CeO2 and Cr2O3 with both fixed and variable
equitorial divergence slits. Here are the results:
CeO2 Cr2O3
fixed variable fixed variable
size 209(5)nm 201(5)nm 241(10)nm 225(8)nm
strain 0.000200(21) 0.000183(19) 0.000334(28) 0.000290(23)
Errors are random only. As I have posted at the WWW site cited above,
the largest remaining error is that of the Cu-K-alpha parametrization.
The method of tube tails correction was somewhat improved since then.
If you are interested, I will try to re-evaluate the measurements
with the up-do-date BGMN level.
Good luck!
J"org Bergmann
[EMAIL PROTECTED]
