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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
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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
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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 398°C and will evaporate if heated to 665°C !! 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.
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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 ============================================
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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
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Selection of substances for temperature calibration -
(courtesy by Dr. M. Emrich)
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