Measurement of the in freezing-point temperature: Effect of the liquid-solid interface structure

Abstract

The results of the experimental study of the inner interface formation process under different conditions of its initiation for the indium freezing point showed that, depending on the initiation intensity, both the planar structure of the interface on the thermometer well and a noticeable intergrowth of dendrites could be obtained. However, under some specific initiation conditions dendrites disappeared partly or completely in the process of crystallization. The value of the indium freezing point temperature was measured under realization conditions corresponding to different inner interface structure

Correlation Between Immersion Profile and Measured Value of Fixed-Point Temperature

“…For example, the bridges can appear over melting and subsequent falling on the cell bottom of the dendrites, formed in the process of the inner interface initiation. The variations of the inner interface structure with full destruction of dendrites were previously studied for an In cell [4]; the presence of dendrites on the cell bottom were found in a Sn cell [10].…”

“…In our previous publications [4][5][6], we have tried to estimate the dependence of the immersion curves and the fixed-point temperature measurement result on the realization conditions, primarily on the shape of the inner interface and its continuity, the method of its initiation, and the moment of the start of the initiation. The results of both experimental and computational investigations revealed the deviation of the temperature gradient on the well inner surface from the theoretical hydrostatic effect even in the presence of the continuous interface around the well.…”

Study of the Inner Phase Interface Structure in an Indium Freezing Fixed Point Cell

“…From the results of experiments, it follows that the form of generating line of the inner boundary and its continuity to the channel walls depends on the initiation method and in the majority of cases does not correspond to the model adopted [4,6]. In addition, it was not possible to detect a complete analogy between phase interface formation conditions within a fi xed point cell with crystallization within large volumes.…”

“…The temperature is close to the substance liquidus temperature, and being an optimum result of measurements is achieved during the fi rst 25% of metal crystallization time. This model is used in order to estimate the uncertainty of temperature measurement results, caused by the effect of impurities within metal and thermal equilibrium between phases.In order to estimate the reliability of the crystallization model adopted, the authors have obtained photographs of the structure of the inner phase interface after initiating an indium freezing point within a cell [4]. The choice of this point is due to the fact that its temperature makes it possible to extract the thermometer from the thermometer channel at different freezing stages and to record the form of the inner boundary.…”

“…In order to estimate the reliability of the crystallization model adopted, the authors have obtained photographs of the structure of the inner phase interface after initiating an indium freezing point within a cell [4]. The choice of this point is due to the fact that its temperature makes it possible to extract the thermometer from the thermometer channel at different freezing stages and to record the form of the inner boundary.…”