Re: Question: particle size and microstrain

Linda D. Mansker ( (no email) )
Sun, 28 Sep 1997 21:35:21 -0600

We've been trying Rietveld refinement on some Al2O3 with particles in that
size range - or rather, someone in my research group is trying. There's a
paper by Robert Snyder (Acta Cryst., Vol. 47, Pg. 617, I think) which
discusses in detail rietveld refinement of several phases (alpha, gamma,
and delta). We used Snyder's work as a starting point - he discusses in
detail, how he dealt with the broad features in the diffraction pattern.
That might help get you started. We've been having slight problems,
ourselves, with size effects. The particle size range in my colleague's
alumina catalysts, as well as those in my catalysts (which are not
containing Al2O3) range from about 30 nm to 200 nm, heavily weighted toward
the smaller particles. So, perhaps we can help you.

I am, unfortunately, leaving for a conference early in the morning, or I'd
devote more time to this. If you don't mind, and can wait, I'll be back
in a week, and can discuss with you further, either through the list, by
phone, or by EMAIL directly.

Linda Mansker

At 11:08 AM 9/29/97 +1000, you wrote:
>Hi Rietveld Users:
>
>I am working in Rietveld and powder structure determination
>
>of the nano Al2O3 particle (about 30nm). Owing to broad, complex pattern it
>is very
>
>difficult to interpret various phases(alpha, gamma, delta and so on).
>
>
>The question is; is it possible to refine structure using the Rietveld
method
>
>though particles are nano? If possible how can it massage?
>
>I am very happy if anyone could inform me of the size effect on Rietveld
>analysis.
>
>
>
>Thanks in advance
>
>
>
>========================================
>Dr. Hyun Min Park
>Materials Evaluation Center,
>Korea Research Institute of Standards and Science
>P.O. BOX 102, Taejon 305-600, Korea
>(TEL) +82-42-868-5277,5293
>(FAX) +82-42-868-5032
>(Email) hmpark@krissol.kriss.re.kr
>========================================
>
>
>
Linda D. Mansker mansker@unm.edu
213 Farris Engineering Center Chemical and Nuclear Engineering Department
PH: (505) 277-5841 Albuquerque, NM 87131-1341
(505) 254-7859 FAX: (505) 277-5433
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