New Method of Filling of High-Temperature Fixed-Point Cells Based on Metal-Carbon Eutectics/Peritectics

Khlevnoy, B. B.; Grigoryeva, Irina; Ibragimov, N. A.

doi:10.1007/s10765-011-0998-7

Cited by 15 publications

(5 citation statements)

References 5 publications

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“…The filling took 19 steps for the Re-C cell and eight steps for the WC-C cell. The other free cells were filled by a 'drop' technique, where the alloy is melted in an extra open container located above the crucible, and then the already formed metal-carbon alloy in a liquid phase fills the crucible drop by drop [12]. The 'drop' filling took 4-5 steps for both Re-C and WC-C cells.…”

Section: Design and Fabrication Of Large Htfp Cellmentioning

confidence: 99%

Development of large-area high-temperature fixed-point blackbodies for photometry and radiometry

et al. 2018

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Large-area high-temperature fixed-point (HTFP) blackbodies with working temperatures of approximately 2748 K and 3021 K, based on an Re-C eutectic and a WC-C peritectic respectively, have been developed and investigated. The blackbodies have an emissivity of 0.9997, show high-quality phase-transition plateaus and have high repeatability of the melting temperatures, but demonstrate temperature differences (from 0.2 K to 0.6 K) compared with small-cell blackbodies of the same HTFP. We associate these temperature differences with the temperature drop effect, which may differ from cell to cell. The large radiating cavity diameter of 14 mm allows developed HTFP blackbodies to be used for photometric and radiometric applications in irradiance mode with uncertainties as small as 0.12% (k = 1) in the visible. A photometer and an irradiance-mode filter radiometer (visible range), previously calibrated at VNIIOFI, were used to measure illuminance and irradiance of the HTFP blackbodies equipped with a precise outer aperture. The values measured by the detectors agreed with those based on the blackbody calculation to within 0.2%. The large-area HTFP blackbodies will be used in a joint PTB-VNIIOFI experiment on measuring thermodynamic temperature.

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Section: Design and Fabrication Of Large Htfp Cellmentioning

confidence: 99%

Development of large-area high-temperature fixed-point blackbodies for photometry and radiometry

et al. 2018

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“…For cell WC-C5 the new 'drop method' [3] developed at VNIIOFI was applied. In this method the mixture is introduced not into the crucible, but into an additional container located just above the crucible.…”

Section: Fabrication Of the Cellsmentioning

confidence: 99%

Development and investigation of WC–C fixed-point cells

Khlevnoy¹,

Grigoryeva²,

Otryaskin³

2012

Metrologia

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Three cells of the WC–C peritectic fixed point with a temperature of about 3021 K were built and investigated. Two different sources of tungsten with nominal purities of 5N and 3N were used, and two different filling techniques were applied. There was no difference in plateau shapes between the cells. The 3N purity cell showed a small difference (0.22 K) in the melting temperature from the 5N cell, which indicates significant purification of initially contaminated tungsten. The typical melting range and repeatability of the observed peritectic melting plateaux were 100 mK and 15 mK, respectively. The melting point was stable and reproducible within 25 mK per two weeks. T90 temperature of the WC–C melting point was found to be (2747.6 ± 1.1) °C (k = 2). The observed freezing plateaux were flat and repeatable within 50 mK and 15 mK, respectively. The WC1−x–WC eutectic transition showed a melting temperature about 29 K lower than the peritectic one with a repeatability of about 0.2 K. The problem of deep supercooling is discussed and a method for its solution is shown and tested.

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“…Dimensions of the cartridge used to introduce the cells into the filling furnace restricted the length of the extension so two filling steps were normally required to fill the crucibles completely, drastically reducing the number of melts required to fill a cell applying the classic drop method, which could reach up to 20 cycles [5]. Both the piston and the pushing rod have a cavity along their axis that allow to evacuate gases present on the powder mixture out of the crucible during its melt and, once the cell is filled and solidified, the excess of ingot present on the mentioned cavity can be used as a sample that can be analyzed using the Glow Discharge Mass Spectrometry (GDMS) technique in order to obtain a quantitative determination of the impurities present on the fixed point.…”

Section: Nrc-cem Cells 21 Cell Designmentioning

confidence: 99%

Construction and comparison of high temperature fixed points at NRC and CEM

Mantilla

Woods

Emms

et al. 2023

J. Phys.: Conf. Ser.

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This paper describes the collaborative project between National Research Council of Canada (NRC) and Centro Español de Metrología (CEM) for the construction and comparison of high temperature fixed points (HTFPs). A hybrid-type crucible that uses the piston method for filling has been jointly developed. A series of 12 high temperature fixed point blackbodies (HTFPBBs) have been constructed, including Cu, Ru-C, Ir-C, Re-C and WC-C covering the temperature range from 1084°C to 2750°C. All these cells were filled in NRC facilities by CEM and NRC staff. Two cells of each type of fixed point were constructed (except for the WC-C cells), using crucibles from two different suppliers in order to study the influence of the density and emissivity of the crucible in the HTFPs’ performance. Moreover, four WC-C cells were made using tungsten powder from two different suppliers, covering all the possible combinations of tungsten powder and crucibles acquired for this project. All cells, and additionally a Pt-C HTFPBB belonging to NRC, have been measured firstly at NRC and, afterwards, at CEM. Both laboratories have calculated the ITS-90 temperatures from their respective measurements and the results have been compared. Differences on the ITS-90 temperatures of the HTFPBBs measured at each lab are within uncertainties of the comparison. After the comparison, CEM kept one Cu cell, one Ru-C cell, one Re-C cell and two WC-C cells. The rest of the fixed points involved in the comparison were sent back to NRC.

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New Method of Filling of High-Temperature Fixed-Point Cells Based on Metal-Carbon Eutectics/Peritectics

Cited by 15 publications

References 5 publications

Development of large-area high-temperature fixed-point blackbodies for photometry and radiometry

Development of large-area high-temperature fixed-point blackbodies for photometry and radiometry

Development and investigation of WC–C fixed-point cells

Construction and comparison of high temperature fixed points at NRC and CEM

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