Construction of Gallium Point at NMIJ

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• 作者：J. V. Widiatmo ; I. Saito ; K. Yamazawa
• 关键词：Fixed points ; Gallium melting point ; Gallium point cell ; International Temperature Scale of 1990 ; Standard platinum resistance thermometer
• 刊名：International Journal of Thermophysics
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：38
• 期：3
• 全文大小：
• 刊物类别：Physics and Astronomy
• 刊物主题：Condensed Matter Physics; Classical Mechanics; Industrial Chemistry/Chemical Engineering; Physical Chemistry;
• 出版者：Springer US
• ISSN：1572-9567
• 卷排序：38

文摘

Two open-type gallium point cells were fabricated using ingots whose nominal purities are 7N. Measurement systems for the realization of the melting point of gallium using these cells were built. The melting point of gallium is repeatedly realized by means of the measurement systems for evaluating the repeatability. Measurements for evaluating the effect of hydrostatic pressure coming from the molten gallium existing during the melting process and the effect of gas pressure that fills the cell were also performed. Direct cell comparisons between those cells were conducted. This comparison was aimed to evaluate the consistency of each cell, especially related to the nominal purity. Direct cell comparison between the open-type and the sealed-type gallium point cell was also conducted. Chemical analysis was conducted using samples extracted from ingots used in both the newly built open-type gallium point cells, from which the effect of impurities in the ingot was evaluated.