[CCP14 Home: (Frames | No Frames)]
CCP14 Mirrors: [UK] | [CA] | [US] | [AU]

(This Webpage Page in No Frames Mode)

CCP14

Methods, Problems and Solutions

Quantitive Phase Analysis and Amorphous Content

The CCP14 Homepage is at http://www.ccp14.ac.uk

[Back to Problems and Solutions]

Via the Rietveld Users' Mailing List

Date: Thu, 06 May 2004 16:56:44 +0200
To: rietveld_l@ill.fr
From: Robert Mauricot

Dear all,

I have a powder diffraction of an amorphous multiphase material. I want
to do a quantitative analysis of the amorphous phase. Can anyone tell me
what software does it.

Sincery

R.mauricot

Cemes-CNRS
Toulouse 31077 France
Laboratoire  NaNomat


Subject:   Re: Quantitive analysis
From: "Jörg Bergmann" 
To: "rietveld_l@ill.fr" 
Date: Thu, 06 May 2004 17:39:08 +0200 (CEST)

On Thu, 06 May 2004 16:56:44 +0200, Robert Mauricot wrote:
>Dear all,
>
>I have a powder diffraction of an amorphous multiphase material. I want to 
>do a quantitative analysis of the amorphous phase.  Can anyone tell me what 
>software does it.

Many Rietveld programs will do so. For example, BGMN
comes with an example for amorphous estimation, see
http://www.bgmn.de/download.html -> http://www.bgmn.de/download/amorph.zip
The principle is using an internal standard of known content.

Sincery

J"org Bergmann, Dresden
email @ jbergmann.de
*** This EComStation system uptime is 2 days 0 hours ***


Subject:   Re: Quantitive analysis
From: Luca Lutterotti
Date: Thu, 6 May 2004 19:55:07 +0200
To: rietveld_l@ill.fr

Analysis without internal standard (for example for bulk materials) can
be done with Maud for glasses of other common amorphous phases.

http://www.ing.unitn.it/~luttero/maud

there is one example, plus a publication on line.

	Luca Lutterotti


Subject:   Quantitive analysis
From: "Whitfield, Pamela"
To: "'rietveld_l@ill.fr'" 
Date: Thu, 6 May 2004 13:44:36 -0400 

Robert

As previously mentioned many Rietveld programs will do what you want if
you're willing to do the amorphous content calculations by hand afterwards.
Some commercial software has it built in.
I've done work in this area, and there are some pitfalls of which you must
be aware, or your results may be VERY unreliable.  

1.  microabsorption.  If your phases are similar in composition and your
'spike' phase has a similar absorption then this might not be a problem.
However, there are instances in which extreme microabsorption can make a
accurate determination practically impossible (other than possibly changing
your tube to a more friendly wavelength).  There is the Brindley correction
that can sort of correct moderate microabsorption, but you need to know your
particle size, and ideally it needs to have a narrow distribution.  Reducing
the particle size of your sample to sub-micron levels helps significantly.

2. spike phase.  Many so-called crystalline phases aren't as fully
crystalline as you might think.  The SRM676 alumina had it's amorphous
content measured a while back using neutrons and came out as 1.77 +- 0.68%.
It doesn't sound alot but can make a big difference to your final results.
Many 'crystalline' phases can be significantly higher.  Microabsorption can
be an issue with the spike so choose your spike carefully, and ideally
standardise it using SRM676.  Remember to include the error in the SRM676
amorphous content if quoting absolute amorphous contents rather than
relative amounts.

3. particle statistics.  This is equally as important when looking at purely
crystalline materials, but errors due to poor particle statistics can really
mess up amorphous content work.  Ideally, micronise your sample before
running it, but if they're nanomaterials then it might not be an issue.

4.  surface roughness.  I noticed that you probably work with nanomaterials.
They tend to be fluffy, and such samples (at least on our instrument) show
noticeable surface roughness effects on low angle reflections. If this is
the case for your samples then you will either have to correct it or densify
your sample somehow (or both).


Some of this stuff was covered in the results of the quantitative analysis
round robin a while back:

Outcomes of the International Union of Crystallography Commission on Powder
Diffraction Round Robin on Quantitative Phase Analysis: samples 1a to 1h
I. C. Madsen, N. V. Y. Scarlett, L. M. D. Cranswick and T. Lwin, J. Appl.
Cryst. (2001). 34, 409-426

Outcomes of the International Union of Crystallography Commission on Powder
Diffraction Round Robin on Quantitative Phase Analysis: samples 2, 3, 4,
synthetic bauxite, natural granodiorite and pharmaceuticals
N. V. Y. Scarlett, I. C. Madsen, L. M. D. Cranswick, T. Lwin, E. Groleau, G.
Stephenson, M. Aylmore and N. Agron-Olshina
J. Appl. Cryst. (2002). 35, 383-400 


It would be useful to cross-check your technique on a couple of dummy
samples if at all possible to make sure you're not being mislead.  Have
fun!!

Pam



Dr Pamela Whitfield CChem MRSC
Energy Materials Group
Institute for Chemical Process and Environmental Technology
Building M12
National Research Council Canada
1200 Montreal Road
Ottawa  ON   K1A 0R6
CANADA
Tel: (613) 998 8462         Fax: (613) 991 2384
Email: mailto: pamela.whitfield @ nrc-cnrc.gc.ca
ICPET WWW: http://icpet-itpce.nrc-cnrc.gc.ca


Subject:   Re: Quantitive analysis
Date: Thu, 06 May 2004 15:43:19 -0400
To: rietveld_l@ill.fr
From: Jim Cline 

Hi all,

This is to say that I'm am nearly finished with the re-certification of SRM 
676 for amorphous content.  The revised certificate, offering a discussion 
as to the certification method, will be on the NIST website shortly, after 
the review process is completed.  The certified phase purity of SRM 676 
(retroactive to units in the field) is 91.75% +/- 1.5%.

Regards,

Jim

James P. Cline                          jcline@nist.gov
Ceramics Division                               Voice (301) 975 
5793
National Institute of Standards and Technology  FAX (301) 975 5334
100 Bureau Dr. stop 8520
Gaithersburg, MD 20899-8523    USA


Subject:   Re: Quantitive analysis
From: "Whitfield, Pamela" 
To: "'rietveld_l@ill.fr'" 
Date: Thu, 6 May 2004 15:48:51 -0400 

Jim

Excellent news!  This amorphous standard issue has been driving me nuts.
When you say phase purity do you mean purity in terms of crystalline phase
content?

Pam

Dr Pamela Whitfield CChem MRSC
Energy Materials Group
Institute for Chemical Process and Environmental Technology
Building M12
National Research Council Canada
1200 Montreal Road
Ottawa  ON   K1A 0R6
CANADA
Tel: (613) 998 8462         Fax: (613) 991 2384
Email:  mailto: pamela.whitfield @ nrc-cnrc.gc.ca 
ICPET WWW: http://icpet-itpce.nrc-cnrc.gc.ca


Date: Thu, 06 May 2004 16:18:09 -0400
To: rietveld_l@ill.fr
From: Jim Cline 

Hi,

At 03:48 PM 5/6/2004 -0400, you wrote:
>Jim
>
>Excellent news!  This amorphous standard issue has been driving me nuts.
>When you say phase purity do you mean purity in terms of crystalline phase
>content?

Yes.

Jim

James P. Cline                          jcline @ nist.gov
Ceramics Division                               Voice (301) 975 
5793
National Institute of Standards and Technology  FAX (301) 975 5334
100 Bureau Dr. stop 8520
Gaithersburg, MD 20899-8523    USA


Subject:   Re: Quantitive analysis
From: "Allen, Douglas"
To: 'rietveld_l@ill.fr'
Date: Thu, 6 May 2004 20:14:07 -0700

Speaking of internal standards.  Can someone recommend a source of bulk
alumina to use for production samples.  I don't find 'linde A' listed in the
Buehler catalog anymore. I'm not sure which of the various grades they list
to order or if there is a better place to order it. 

Doug Allen
Usually just lurking on this list


Subject:   Re: Quantitive analysis
Date: Fri, 7 May 2004 13:44:50 +1000
From: Ian Madsen 
To: rietveld_l@ill.fr

Doug,

We used commercially available alpha-Al2O3 (corundum) for the recent
IUCr-CPD round robin on quantitative phase analysis. The source details
are :-

	Bailalox alumina polishing powder
	Baikowski International Corporation
	Standard C  1.0 micron (scratch size - actual particle size approx 28micron)

It is available in commercial quantities and from memory was not very
expensive. Independent checks suggest it was better than 99%
crystalline.

For further details see the first round robin paper - Madsen et al.
J.Appl Cryst (2001) 34, 409-426.

Cheers

o----------------------oo0oo---------------------------o
     Ian Madsen
        Science Adviser - Analytical Science
        CSIRO Minerals
        Box 312
        Clayton South    3169
        Victoria
        AUSTRALIA

     Phone	+61 3 9545 8785  direct
		+61 3 9545 8500  switch
		0417 554 935   mobile
     FAX	+61 3 9562 8919
     Email  ian.madsen@csiro.au
o----------------------oo0oo---------------------------o


[Back to Problems and Solutions]

[CCP14 Home: (Frames | No Frames)]
CCP14 Mirrors: [UK] | [CA] | [US] | [AU]

(This Webpage Page in No Frames Mode)

If you have any queries or comments, please feel free to contact the CCP14