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Physical and technological preconditions of melting-crystallisation temperature stabilisation

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Purpose: The precise temperature measurements need the using of temperature reference points - "temperature fixpoints" (TFP). The increase of measuring temperature interval and other reasons require of new TFP with high stability in different working conditions. On that reason the studying of liquid metals and metallic eutectic alloys has been carried out in this work. Design/methodology/approach: For experimental studies the physical properties measurements were used. Findings: Non-reproducibility of temperature fixpoints exist due to some reasons: no accounting the structural - thermodynamic state of melt; mass-heat processes are not enough taken into account. It is fixed, that the temperature fluctuations (and non-stability of crystallization plateau) are of two types: small fluctuations (up to (1-2) mK) are caused by phases (stages) of crystallization process; major fluctuations (at us: ±0,2K) crystallizations are caused convectional streams at the front. Fluctuations can be essentially reduced by approach to requirements of thermodynamic balance, but their complete elimination - is problematic. Research limitations/implications: The main parameters obtained from them are analysed. It is shown that melting-crystallization phase transition is influenced by structural state of melt and cooling condition. Practical implications: The results obtained here can be used in analysis of errors at high-precision temperature measurements and constructing of new temperature measuring and holding systems of high stability. Originality/value: The results of this study can be useful for researches in field of metrology, material science and physics of metals.
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Bibliogr. 8 poz.
  • Physics of Metals Department, National University „Lvivska Politechnika“, 12 Bandera St., Lviv, 290646, Ukraine,
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  • [5] S. Mudry, V. Prokhorenko, S. Prokhorenko, Z. Bojar, Influence of structure state of melt on solidification process, Journal of Achievements in Materials and Manufacturing Engineering 18 (2006) 159-162.
  • [6] V.Y. Prokhorenko, V.V. Roshchupkin, M.A. Pokrasin, S.V. Prokhorenko, V.V. Kotov, Liquid gallium: potential uses as a heat-transfer agent, High Temperature 38/6 (2000) 954-968.
  • [7] S. Prokhorenko, V. Prokhorenko, S. Mudry, W. Halczak, A. Panas, T. Lutsyshyn, J. Wojturski, Effects of outside energetic treatment of metal melts on the process of crystallization, analyzed by AE-method and melting plateau stabilization, Journal of Materials Processing Technology 174-175 (2006) 341-344.
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