Abstract
Fifteen miniature fixed-point cells made of three different ceramic crucible materials (\(\hbox {Al}_{2}\hbox {O}_{3},\, \hbox {ZrO}_{2}\), and \(\hbox {Al}_{2}\hbox {O}_{3} (86\,\%)+\hbox {ZrO}_{2}\) (14 %)) were filled with pure palladium and used for the calibration of type B thermocouples (Pt30%Rh/Pt6%Rh). The melting behavior of the palladium was investigated by using different high-temperature furnaces usable in horizontal and vertical positions. It was found that the electromotive forces measured at the melting temperature of palladium are consistent with a temperature equivalent of ±0.25 K when using a furnace with an adequate temperature homogeneity (±1 K over a length of 12 cm), independent of the ceramic crucible materials. The emfs measured in the one-zone furnaces with larger temperature gradients along the crucibles are sensitive related to the position of the crucibles in the temperature gradient of these furnaces. This is caused by higher parasitic heat flux effects which can cause measurement errors up to about \(\text {-}\)(1\(\text {-}\)2) K, depending on the thermal conductivity of the ceramic material. It was found that the emfs measured by using crucibles with lower thermal conductivity \((\hbox {ZrO}_{2})\) were less dependent on parasitic heat flux effects than crucibles made of material of higher thermal conductivity \((\hbox {Al}_{2}\hbox {O}_{3})\). The investigated miniature fixed points are suitable for the repeatable realization of the melting point of palladium to calibrate noble metal thermocouples without the disadvantages of the wire-bridge method or the wire-coil method.
Similar content being viewed by others
References
B.K. Bragin, Calibration of rare-metal thermocouples against the melting point of palladium, translated from Izmeritel’naya Tekhnika. No. 12, 15–18 (1960)
R.E. Bedford, Reference tables for platinum 20% Rhodium/Platinum 5% Rhodium thermocouples. Rev. Sci. Inst. 35, 1177 (1964). doi:10.1063/1.1718993
M. Gotoh, M. Ogawa, J. Ode, Improved uncertainty of palladium wire bridge method (XVI IMEKO World Congress, Vienna, 2000)
Y.-G. Kim, K.S. Gam, K.H. Kang, Realization of the palladium freezing point for thermocouple calibrations. Metrologia 36, 465–472 (1999)
R.E. Bedford, G. Bonnier, H. Maas, F. Pavese, Recommended values of temperature on the International Temperature Scale of 1990 for a selected set of secondary reference points. Metrologia 33, 133–154 (1996)
T.P. Jones, K.G. Hall, The melting point of palladium and its dependence on oxygen. Metrologia 15, 161–163 (1979)
L. Crovini, R. Perissi, J.W. Andrews, C. Brooks, W. Neubert, P. Bloembergen, G. Voyer, I. Wessel, Intercomparison of platinum thermocouple calibration. High Temp. High Press 19, 179–194 (1987)
F. Jahan, M. Ballico, The mini-coil method for calibration of thermocouples at the palladium point, in Temperature: Its Measurement and Control in Science and Industry, vol. 7, ed. by D.C. Ripple (AIP, New York, 2003), pp. 523–528
H. Ronsin, M. Elgourdou, Extension of the Minicell Thermocouple Calibration Technique to the Palladium Fixed-Point, Proc. TEMPMEKO 1996 (Ed. P Marcarino, Levrotto & Bella, Torino) 189-193
F. Edler, Miniature fixed points at the melting point of palladium, in Proc. TEMPMEKO 1996, ed. by P. Marcarino (Levrotto & Bella, Torino, 1997), pp. 183–188
http://www.bce-special-ceramics.de/hochleistungskeramik/vergleich/
Author information
Authors and Affiliations
Corresponding author
Additional information
Selected Papers of the 13th International Symposium on Temperature, Humidity, Moisture and Thermal Measurements in Industry and Science.
Rights and permissions
About this article
Cite this article
Edler, F., Huang, K. The Melting Point of Palladium Using Miniature Fixed Points of Different Ceramic Materials: Part I—Principles and Performances. Int J Thermophys 37, 126 (2016). https://doi.org/10.1007/s10765-016-2134-1
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/s10765-016-2134-1