Novel High temperature Metal-carbon Eutectic fixed points for Radiation Thermometry, radiometry and thermocouples (HIMERT)

Final Report, 18 March 2005

This is the closing report of Euromet project 550.

The project is nearing completion on schedule. The formal closing date is the end of April with all the formalities to be concluded with the EU by the end of June.

The final meeting of HIMERT is to be held at PTB on 13th April followed by a workshop on “High Temperature Fixed-points for Industrial and Scientific Applications” on 14th and 15th April.

A follow on Euromet project in contact thermometry is currently in discussion with LNE and PTB.

The radiation thermometry part of the project will be taken forward under the auspices of CCT-WG5. A coordinated work plan to take this research forward on an international basis will be presented to the CCT-WG5 on 8th June.

This project has been highly successful in establishing in Europe a competent technical knowledge base in M-C eutectic technology. Issues such as construction, repeatability, intra-cell repeatability, modeling, non-contact and contact thermometry applications have all been addressed in this project with significant progress being made in all these areas. In addition close liaison with NMIJ has also been maintained throughout the duration of the project to mutual benefit.


Progress, June 2004

The partners have made significant progress in this project.

The partners have now made the following cells:

For Radiation Thermometry
1) Re-C, Ru-C, Pt-C, Pd-C and Co-C and attempted MoC-C (NPL).
2) Re-C, Ru-C, Pt-C, Pd-C and Co-C (BNM-INM)

For contact (thermocouple) thermometry
1) Co-C, Ni-C, Pd-C, Pt-C and Ru-C (BNM-LNE)

NPL has performed a comparison of ITS-90 with NIST (USA) with its cells and the scale agreement was clearly <0.5 °C over the range 1320°C to 2500 °C, indicating that despite using radically different equipment it is possible to realize ITS-90 at high temperatures at the sub 1°C level. Cells of NPL, BNM-INM and NMIJ (Japan) were compared and their absolute temperatures measured at PTB in May 2004, the results are still being processed.

Measurements by BNM-LNE of Pt-C and Ru-C with a W-Re thermocouple demonstrate the utility of the cells for the testing and calibration of these sensors, which are notorious for their drift rates.

The UoV has performed modeling which indicates that the temperature drop due to radiance loss as predicted by the simple model is a gross overestimate of the real situation. Also modeling of doped silver using MTDATA has confirmed the modeling veracity of the program, particularly in predicting temperature drop with impurity level. However the modeling is not so successful at predicting the behaviour of M-C eutectics, recent annealing studies have shown that this may be due to grain structure not accounted for in the models.

LAND has constructed two thermometers for testing traceability schemes, one traditional one based on eutectics. It now has a large area Co-C point at its premises for proof testing its pyrometers at 1324 °C.

At the recent Tempmeko 04 conference nine papers were presented arising from this project.


Progress, June 2002

Initially, this project was intended to study the ability of carbon-metal eutectics to be used as high-temperature reference points in radiation thermometry and for contact thermometry.

During the past two years, in the frame of this project, the partners have harmonised their studies in order to achieve a comparison of their realisations. Moreover, metal-carbon eutectic point cells were and are being constructed at NPL, and BNM-INM for radiation thermometry and at BNM-LNE for contact thermometry.

The first results obtained proved very promising and encouraged the partners to enlarge the objectives of our cooperation and to envisage additional funding in order to give an impulse to the project.

Consequently, a proposal was prepared among the consortium and submitted in March 2001 under the title “Novel HIgh temperature Metal-carbon Eutectic fixed points for Radiation Thermometry, radiometry and thermocouples (HIMERT)” to the European Commission, under the Framework 5 Competitive and Sustainable Growth Programme (Growth), and was selected for funding in July 2001. HIMERT was formally started with a kick-off meeting at the University of Valladolid (UV) in January 2002. The number of partners increased to include direct industrial participation (LAND Instruments and Thermocoax) and one partner (UV) is specifically charged with a theoretical elaboration of the eutectic process.

The main aims of HIMERT project is to answer these questions :-

Is the eutectic point phase change repeatable and reproducible ?
What are the systematic errors that may affect the plateau (due to impurities, temperature uniformity,…)?
What would be the eventual applications of these cells within NMIs (support for comparisons, future fixed points,…) and for Industry (means for ensuring traceability) ?
Would there be important differences between different realizations (thermodynamic temperature as well as ITS-90 temperature)?

In view of these changes the title of the project is changed to that of the EU project, the end date is extended to that of the EU project (Dec 04) and because Graham Machin of NPL is the coordinator of the EU project it is sensible for him to be the coordinator of this project – this was agreed at the last EUROMET Contact Persons meeting in April 2002.


Project Description

Initially, this project was intended to study the ability of carbon-metal eutectics to be used as high-temperature reference points in radiation thermometry and for contact thermometry.

The implementation of such fixed point cavities will first require the study of new filling techniques, the investigation of the compatibility of the cavity materials, the assessment of the reproductibility of the phase transition temperature and the determination of the thermodynamic temperature of the transitions.

Subjects
Thermometry (T)
Coordinating Institute
NPL (United Kingdom)
Further Partners
University of Valladolid
Land Instruments International
Thermocoax