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Methods, Problems and Solutions

High Temperature powder diffraction standards

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Subject:   Reference Materials for temperature Calibration.
From: "Namsoo Shin"  
To: rietveld_l@ill.fr
Date: Fri, 7 May 2004 00:20:46 +0900

Dear all

Can anyone tell me reference powders for XRD temperature calibration in
th range from R.T to 1000 degreeC?

Thanking in advance

Namsoo Shin 


Subject:   Reference Materials for temperature Calibration.
Date: Fri, 7 May 2004 09:40:06 +1000
From:  Ian Madsen 
To:  rietveld_l@ill.fr 

Namsoo,
 
Robert Dinnebier has an extensive list of materials and their transition
points (some solid-solid phase transitions, some melting) on his
web-site at:-
 
    http://www.mpi-stuttgart.mpg.de/xray/html/temperature_calibration.html
 
Alternatively, the book "X-ray Diffraction at Elevated Temperatures"
Chung, deHaven, Arnold, Ghosh, VCH Publishers, ISBN 0-89573-745-0 has a
less extensive list on page 148.
 

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 


Subject:   Reference Materials for temperature Calibration.
Date: Mon, 10 May 2004 09:58:05 +0200
From: "Van den Berghe Sven" 
To: rietveld_l@ill.fr

Dear all,
 
Be careful with the list on page 148 of the book cited below. There is
an error in the list that can cause you big problems ! The compound
K2Cr2O7 has a melting point of 398C and will evaporate if heated to
665C !! The compound they actually refer to is K2CrO4 !
 
I can tell you, decontaminating a heating stage coated with chromate is
not much fun !
 
Cheers,
 
Sven 

>Alternatively, the book "X-ray Diffraction at Elevated Temperatures"
>Chung, deHaven, Arnold, Ghosh, VCH Publishers, ISBN 0-89573-745-0 has a
>less extensive list on page 148.


Subject:   RE: Reference Materials for temperature Calibration.
From: "Michael Nippus"  
To:  rietveld_l@ill.fr 
Date: Mon, 10 May 2004 12:19:08 +0200

Re: Reference Materials for temperature Calibration. There was a ICDD 2003
Meeting Report, see Powder Diffr., Vol. 18, No. 2, p189, where Scott T.
Misture presented some "preliminary results on generating full temperature
calibration curves" on XRD. Scott is Chair of The Task Group on High
Temperature Calibration, he wrote. May be he has more publishable works, in
the meantime.

mailto:misture@xray.alfred.edu


Cheers

============================================
Dr. Michael Nippus
Huber Diffraktionstechnik GmbH & Co. KG
Sommerstrasse 4
D-83253 Rimsting / Chiemsee, Germany
http://www.xhuber.com
Tel: +49(0)8051 68780
Fax: +49(0)8051 687810
============================================


Subject:   Reference Materials for temperature Calibration.
Date: Thu, 06 May 2004 20:08:05 -0400
From: Andrew Payzant 
To: Rietveld list  rietveld_l@ill.fr 

This depends on exactly what you want to calibrate, and how. Do you want an
external standard to characterize the instrument, or an internal standard to
improve your accuracy for refining a particular sample diffraction pattern,
or something else again?

There are many choices for standards. You can use known melting point or
phase transformations to establish particular temperature calibration
points, or use lattice parameters and thermal expansion data to cover a
large range. A standard with a large thermal expansion coefficient reduces
your uncertainty in temperature calibration. Of course, in some situations
you might prefer a low or near zero thermal expansion coefficient material
to calibrate the 2theta rather than the temperature.

MgO is a good choice for temperature calibration for many situations  large
thermal expansion coefficient and relatively unreactive with many samples.
Noble metal powders (Pt, Au, Ag) are also useful, but you need to be
extremely wary of melting points and reactivity with heater, sample, and
atmosphere. Even LaB6 can be very useful for these calibrations (up to about
800degC). I recall that Andy Drews from Ford Research Labs had a paper in
Advances in X-ray Analysis a couple of years ago using a 2-standard method
for calibration. You might look into that.

If you are using a strip heater you can use the difffraction from the strip
itself to confirm the calibration of your thermocouple, but your sample
temperature will very likely be different  from the strip temperature in
this case, even for a thin powder layer. For thick powders or
polycrystalline solids the temperature difference is usually more severe.

If you send me more details on what you are planning (Instrument, furnace
type, sample chemistry, etc) I might be able to give a more detailed answer.

Best regards,

Andrew
-- 
E. Andrew Payzant
Senior R&D Staff Member
Metals & Ceramics Division
Oak Ridge National Laboratory
1 Bethel Valley Road
PO Box 2008, MS 6064
Oak Ridge, TN, 37831-6064

ph: (865) 574-6538   FAX: (865) 574-3940
web:  http://html.ornl.gov/dtpgrp/staff/payzant.html 


Selection of substances for temperature calibration - (courtesy by Dr. M. Emrich)
  • At http://www.mpi-stuttgart.mpg.de/xray/html/temperature_calibration.html

  • Material Phase transition/Melting Point Temperature/C
    -------------------------------------------------------------

    NH4NO3 orth. ==> tetr.; humid 84.2 ==> kub.; humid, dry 125.2

    TlNO3 orth. ==> trig. 79 ==> kub. 143

    KNO3 orth. ==> trig. 128

    CsNO3 trig. ==> kub. 160

    RbNO3 trig. ==> kub. 164 kub. ==> tetr. 219

    tetr. ==> kub. 291

    AgNO3 orth. ==> trig. 165

    Sn 231.9

    KClO4 orth. ==> kub. 295.7

    Pb 327.5

    KNO3 333.6

    Zn 419.6

    Ag2SO4 orth. ==> hex. 427

    CuCl 430.0

    Quartz trig. ==> hex. (a ==> ) 573.0

    Sb 630.5

    Al 660.2

    KCl 776

    NaCl 804 3

    Bi2O3  820

    Ag 962.0

    NaF 988.0

    Au 1064.4

    K2SO4  1069

    Cu 1083.0

    CaF2 1360

    Ca2SiO4a ==> a ' 1425 10

    Ni 1453

    Co 1495

    Fe 1535

    Ti 1675

    Zr 1852

    Cr 1890

    Rh 1966

     

    BN : expansion coefficient in c- direction for T = 20 ... 900C : c = 6.6516 + 2.74 * 10-4 * T

     

    Literature :

    1) Klug, H.P., Alexander, L.E.: "X-Ray Diffraction Procedures", Second Edition,

    Wiley Intersc., 1973

    2) McLaren, A.C.: Rev. Pure Appl.Chem., 12(1962), 55-71

    3) Pistorius, C.W.F.: Journ. of Chem. Phys., 46(1967)6, 2167-2172

    4) Tomaszewski, P.E.: Structural Phase Transitions in Crystals, I. Database,

    in: Phase Transitions 38(1992)3,127-221

     


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