Pearce, J V (2016) Optimising platinum-rhodium thermocouple wire composition to minimise composition change due to evaporation of oxides determining the optical composition as a function of temperature. Johnson Matthey Technol. Rev., 60 (4). pp. 238-242.

Full text not available from this repository.

Abstract

Barring the presence of significant amounts of impurities, an important cause of thermoelectric inhomogeneity and therefore calibration drift of Pt-Rh thermocouples at high temperatures is the vaporisation and transport of the oxides of Pt and Rh, which causes local changes in wire composition. By examining the vapour pressures of Pt and Rh oxides and their temperature dependence, it is shown that at a given temperature there is an optimal wire composition at which evaporation of the oxides has no effect on the wire composition. This may also have applications for Pt-Rh heater elements.

Item Type:	Article
Keywords:	Thermocouple, Pt-Rh, drift, temperature
Subjects:	Engineering Measurements Engineering Measurements > Thermal
Identification number/DOI:	10.1595/205651316X692662
Last Modified:	02 Feb 2018 13:13
URI:	https://eprintspublications.npl.co.uk/id/eprint/7314