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Industrial Group of the BCA
August 2000 - techniquesCalibration of temperature in non ambient experimentsAt the recent workshop on controlled environment XRD a request was made to keep a list of materials to calibrate the temperature of a non ambient diffraction machine. It is intended to keep this list updated by adding to it any data supplied by users that they have successfully used for calibration. The current list has been built up over recent years at successive non ambient workshops. Send any additions or corrections to [email protected] The list has been split into two parts.
(1) The International Temperature Scale 1990 list which gives very accurate inform
ation mainly on freezing point and often used for the accurate calibration of thermocouples. (1)International Temperature Scale 1990 (ITS90)Fixed Point State Temp K Temp �C Mercury Triple Point 234.3156 -38.8344 Water Triple Point 273.16 0.01 Gallium Melting Point 302.9146 29.7646 Indium Freezing Point 429.7485 156.5985 Tin Freezing P oint 505.078 231.928 Zinc Freezing Point 692.677 419.527 Aluminium Freezing Point 933.473 660.323 Silver Freezing Point 1234.93 961.78 Gold Freezing Point 1337.33 1064.18 Copper Freezing Point 1357.77 1084.62 (2)Phase change Calibration materialsMaterial Temperature�C Transition KNO3 129 Tr>Trig KClO4 300 ortho>cubic Pb 327 melt KNO3 334 melt PbTiO3 490 Tet>cubic K2SO4 5 83 ortho>hex K2Cr2O7 665 ortho>hex KI 681 melt NaCl* 801 melt BaCO3 810 ortho>cubic Fe 910 bcc>fcc Mn 1135 fcc>bcc CaF2 1360 melt * Note it has been reported that sublimation can be a problem with cool surfaces being covered in a deposit of NaCl Dave Taylor |
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