JP Journal of Heat and Mass Transfer
Volume 13, Issue 1, Pages 23 - 32
(February 2016) http://dx.doi.org/10.17654/HM013010023 |
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EXPERIMENTAL STUDY OF PHASE TRANSITIONS IN FIXED POINTS
T. Nemeth, S. Nemeth and E. Turzo-Andras
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Abstract: The time evolution of the solid fraction and melt fraction along the phase transformation has been followed, using a new technique based on the difference of the electrical conductivity between the solid and liquid phases of the metal. The work has been performed within the framework of the European project “Novel Techniques for Traceable Temperature Dissemination”.
The measurement results provide solutions to one of the pressing problems associated with high level practical temperature metrology, covering the temperature range from –39°C to 962°C. The time evolution of the solid fraction and melt fraction along phase transformation can be followed by studying their difference in electrical conductivity, while the fixed-point temperature remains constant.
This experimental study permits the selection of the ideal section of a melting or freezing plateau, and is, particularly, suited to increase the duration of this temperature plateau-section from a few hours to practically unlimited for all metal fixed points. Thus, achievements in the measurement of temperatures lead to improved stability in processes, where temperature is a critical factor. |
Keywords and phrases: phase transition, fixed points, electrical conductivity. |
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