The Freezing Point of Silver

Abstract Au/Pt thermocouples are considered as an alternative to High Temperature Platinum Resistance Thermometers and are one of the prime candidates to replace them as the interpolating instrument of the International Temperature Scale of 1990 (ITS-90) in the temperature range between about 660 °C and 962 °C. This work presents the results of investigation of two Au/Pt thermocouples that used exclusively quartz glass (SiO2) as insulation material. Measurements in fixed points of Zn, Al, and Ag were realized on these thermocouples as well with interchanged inner insulation made of high purity aluminium oxide (Al2O3). The conducted experiments tested the performance of Au/Pt thermocouples with the use of different insulation materials. The measured electromotive forces were found to be sensitive to the replacement of the quartz glass by aluminium oxide as an insulation material of the Au/Pt thermocouples. This change of insulation has resulted in a temperature increase up to about 0.5 K measured at the freezing point of silver. The decreasing insulation resistance of quartz glass at higher temperatures is believed to be the source of thermoelectric instability.

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Uncertainty evaluation on the freezing point of silver for thermocouple calibration

Proceedings of the 41st SICE Annual Conference. SICE 2002. ◽

10.1109/sice.2002.1195315 ◽

2003 ◽

Author(s):

H. Numajiri ◽

H. Ogura ◽

M. Izuchi ◽

M. Arai

Keyword(s):

Freezing Point ◽

Uncertainty Evaluation ◽

Thermocouple Calibration ◽

Freezing Point Of Silver

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Dissemination of thermodynamic temperature above the freezing point of silver

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2015.0043 ◽

2016 ◽

Vol 374 (2064) ◽

pp. 20150043 ◽

Cited By ~ 5

Author(s):

M. Sadli ◽

G. Machin ◽

K. Anhalt ◽

F. Bourson ◽

S. Briaudeau ◽

...

Keyword(s):

Temperature Scale ◽

Freezing Point ◽

Research Programme ◽

Thermodynamic Temperature ◽

Joint Project ◽

Metrology Research ◽

Mise En Pratique ◽

High Temperature Fixed Points ◽

Freezing Point Of Silver ◽

Definition Of

The mise-en-pratique for the definition of the kelvin at high temperatures will formally allow dissemination of thermodynamic temperature either directly or mediated through high-temperature fixed points (HTFPs). In this paper, these two distinct dissemination methods are evaluated, namely source-based and detector-based. This was achieved by performing two distinct dissemination trials: one based on HTFPs, the other based on absolutely calibrated radiation thermometers or filter radiometers. These trials involved six national metrology institutes in Europe in the frame of the European Metrology Research Programme joint project ‘Implementing the new kelvin’ (InK). The results have shown that both dissemination routes are possible, with similar standard uncertainties of 1–2 K, over the range 1273–2773 K, showing that, depending on the facilities available in the laboratory , it will soon be possible to disseminate thermodynamic temperatures above 1273 K to users by either of the two methods with uncertainties comparable to the current temperature scale.

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The equilibrium diagram of the system silver-zinc

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1941.0001 ◽

1941 ◽

Vol 177 (969) ◽

pp. 149-167 ◽

Cited By ~ 16

Keyword(s):

Freezing Point ◽

Equilibrium Diagram ◽

Freezing Range ◽

Phase Boundaries ◽

X Ray ◽

Whole Number ◽

Equiatomic Alloy ◽

Freezing Point Of Silver ◽

Ray Methods

The equilibrium diagram of the system silver-zinc has been investigated by thermal, microscopic, and X-ray methods. This has enabled the following points to be established: (1) The depression of the freezing-point of silver by zinc is slightly greater than that produced by equal atomic percentages of indium. This does not confirm the hypothesis of whole-number liquidus factors previously suggested by Hume-Rothery, Mabbott and Channell-Evans (1934). (2) The solidus and liquidus curves for the β -phase do not coincide at 50 atomic % of zinc as was proposed by B. G. Petrenko (1929). The freezing range of the equiatomic alloy is approximately 3 1/2 °. (3) The determination of phase boundaries by X-ray methods with quenched filings is unreliable for this class of alloy, and its limitations are discussed.

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