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Standard Reference Material 1745: Indium Freezing-Point Standard and Standard Reference Material 2232: Indium DSC Melting-Point Standard

Published

Author(s)

Gregory F. Strouse

Abstract

The freezing point of indium (156.5985 degrees C) is a defining fixed point of the International Temperature Scale of 1990 (ITS-90). Realization of this freezing point is performed using a fixed-point cell containing high-purity (greater than or equal to 99.999 % pure) indium. A single lot of indium (greater than or equal to 99.999 % pure) constituting Standard Reference Material (R) (SRM) 1745 and SRM 2232 has been evaluated, and certified as suitable for use in the realization of the freezing-point temperature of indium for the ITS-90. Based on results obtained with two fixed-point cells containing random samples of SRM 1745 and one fixed-point cell containing random samples of SRM 2232, the expanded uncertainty (k = 2) assigned to the freezing-point temperature of the metal is 0.34 m degrees C. In this document, the methods used for the fabrication of the indium freezing-point cells and for the evaluation of SRM 1745 and SRM 2232 are described.
Citation
Special Publication (NIST SP) - 260-132
Report Number
260-132

Keywords

indium, SRM, SRM 1745, SRM 2232, Standard Reference Material

Citation

Strouse, G. (2001), Standard Reference Material 1745: Indium Freezing-Point Standard and Standard Reference Material 2232: Indium DSC Melting-Point Standard, Special Publication (NIST SP), National Institute of Standards and Technology, Gaithersburg, MD (Accessed March 28, 2024)
Created June 1, 2001, Updated October 16, 2008