Title: Report on the characterisation of the protection against contamination
Authors: Jursic, Ivan, Physikalisch-Technische Bundesanstalt (PTB), Fachbereich 7.4, Temperatur
Rudtsch, Steffen, Physikalisch-Technische Bundesanstalt (PTB), Fachbereich 7.4, Temperatur
Contributors: HostingInstitution: Physikalisch-Technische Bundesanstalt (PTB), ISNI: 0000 0001 2186 1887
Resource Type: Text / Report
Publisher: Physikalisch-Technische Bundesanstalt (PTB)
Rights: Download for personal/private use only, if your national copyright law allows this kind of use.
Dates: Available: 2021-06-22
Created: 2013-08-31
File: Download File (application/pdf) 777.43 kB (796088 Bytes)
MD5 Checksum: dda193ee833e8e8393164646895dbf83
SHA256 Checksum: 1082dfbb3420ca035952c9904fff83ec3fc197e4efbf6dc98274aa245d0662ff
Keywords Platinum Resistance Thermometer ; oxidation ; contamination
Abstract: Platinum resistance thermometers (PRT) are used over a wide range of temperatures in a wide array of applications. One aim of this work package was to investigate processes leading to instabilities and drift of platinum resistance thermometers.
The sources for this are manifold and one has to investigate the processes with the most significant impact. These processes can be distinguished into two groups; materials and operation procedures.
Impurities can be categorised into the first group of processes and were investigated as step 1.1.1 of Task 1.1. In short summary, even though high purity platinum is used for thin film sensorsa several impurities were found in the investigated thin film sensors prior to any ageing. Ageing experiments at 700 °C were carried out in air and MgO powder. These experiments showed an increased drift of the Pt thin film sensors which were embedded in the MgO powder. X-ray fluorescence analysis (XRF) revealed Fe, Cr, Ni, Ag, Mg and Cu being present in the sensors. Sensors which were aged in the MgO powder had a significantly increased Mg content indicating a poisoning of the sensors by the ceramic powder. A direct relation though is not possible as the other impurities are known to cause drift of PRT’s, but the location of them in the sensors, i.e. Pt conductor lanes or Al2O3 substrate, cannot be determined.
For this report we will focus on two other aspects concerning the influences on the stability of PRT’s. The first one is about the effect the surrounding atmosphere can have on platinum, i.e. oxidation of platinum and reduction of its oxides. The second one is about the impact operating conditions can have on PRT’s, where ageing experiments are carried out to investigate handling to improve stability of the thermometers.
Citation: Jursic, Ivan ; Rudtsch, Steffen. Report on the characterisation of the protection against contamination, 2013. Physikalisch-Technische Bundesanstalt (PTB). DOI: https://doi.org/10.7795/120.20210622