| Download | - View accepted manuscript: High-temperature platinum resistance thermometry: the problem with silver and the case for gold (PDF, 1.7 MiB)
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| DOI | Resolve DOI: https://doi.org/10.1088/0026-1394/52/4/478 |
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| Author | Search for: Hill, Kenneth D.1 |
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| Affiliation | - National Research Council of Canada. Measurement Science and Standards
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| Format | Text, Article |
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| Subject | platinum resistance thermometer; silver fixed point; gold fixed point; contamination |
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| Abstract | The diffusion of silver through quartz at high temperatures leads to contamination of the platinum sensing element of high temperature platinum resistance thermometers. While some protection of the PRT element may be afforded by the application of appropriate electric fields, the contamination of the quartz elements of silver fixed points causes their premature failure. Contamination is evidenced by the yellowish colour imparted to the glass by the silver particles growing within the quartz glass matrix. The presence of silver as the contaminating element has been confirmed unambiguously through energy dispersive x-ray analysis and secondary ion mass spectrometry. To mitigate the risk of silver contamination , the gold point is proposed as an alternative calibration point. PRT resistance ratios measured at the freezing points of silver and gold in different laboratories at different times are highly correlated. This suggests that the ITS-90 reference function might be extrapolated to 1064.18 °C (the gold fixed point). However, it remains unclear from the gold and silver PRT resistance ratios from the literature whether extrapolation of the reference function leads to the correct value at the gold point. A direct comparison of gold fixed points may be required to resolve the inconsistencies. Additional PRT data may help resolve the discrepancy. |
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| Publication date | 2015-05-07 |
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| In | |
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| Language | English |
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| Peer reviewed | Yes |
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| NPARC number | 21275087 |
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| Export citation | Export as RIS |
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| Report a correction | Report a correction (opens in a new tab) |
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| Record identifier | 5009fce3-2cca-463a-8b49-76b6b9d17165 |
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| Record created | 2015-05-07 |
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| Record modified | 2020-06-04 |
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