高精度复现铟凝固点

Highly Precise Realization of the Indium Freezing Point

利用金属外壳密封铟点容器,采用连续热流密度法,高精度复现了铟熔化温坪和凝固温坪。通过线性拟合方法确定铟的液相温度,并将其与凝固温坪最大值之间的差异作为评判铟点容器质量的重要依据。实验结果表明:液相温度和凝固温坪最大值之间的差异在0.27 mK范围内一致;距离容器温度计阱底部16 cm内垂直温场均匀度为13 mK。因此,该金属外壳铟点容器可以满足高精度温度量值传递需求。此外,研究了炉温设定对铟凝固温坪时长及过冷度的影响。

A stainless-steel-cased indium cell was utilized to precisely realize the indium melting and freezing plateaus using a continuous heat flux method.The liquidus temperatures of indium were determined by one linear fitting method,and the differences between the liquidus temperatures and the maximum values of the freezing plateaus were regarded as indicators for evaluating the quality of the indium cell.The results showed that these differences were within 0.27 mK.Also,the vertical temperature uniformity within 16 cm from the thermometer well bottom did not exceed 13 mK.Therefore,the stainless-steel-cased cell can meet the requirements for high-precision temperature dissemination.In addition,the influence of furnance setting temperatures on the duration of the freezing plateau and supercooling were also studied.