A selective multiple fit method of the point of inflection for the large-area HTFP melting plateau curve

Xie, Yihang; Dai, Chen; Wang, Yanfei; Wu, Zhifeng; Li, Ling; He, Shaoming

doi:10.1016/j.measurement.2020.108576

Cited by 3 publications

(4 citation statements)

References 21 publications

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“…Traditionally, the aforementioned methods have been developed to calculate the POI of the melting plateau of smallarea cells with a duration of a few minutes. Recently, in [29], a new selective multiple fit method for evaluating the largearea HTFP melting plateau was proposed and implemented. Similar to the previous method [5], this method also uses firstand second-order derivatives of the melting plateau to determine the start and end points but uses an interval between the inner and outer limits as a fitting range for a third-order polynomial fit.…”

Section: The Point Of Inflection (Poi)mentioning

confidence: 99%

Large-area Fe–C eutectic fixed-points for radiation and contact thermometry

Can,

Gözönünde,

Arifoviç

et al. 2023

Meas. Sci. Technol.

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High-quality metal (carbide)–carbon eutectic materials based on high-temperature fixed points (HTFP) are widely used in radiometry and thermometry as reference standards. HTFPs on the base of Iron-carbon (Fe–C) binary eutectic alloys, with a nominal melting temperature of about 1154 °C (just above the copper freezing point of 1084.62 °C), are one of the promising candidates among the eutectic materials. To establish new HTFPs as reference metrological tools for high-temperature thermometry, their performance should be thoroughly investigated regarding reproducibility and stability. In this work, two large-area (8 mm aperture, 107 mm cavity/thermowell length) Fe–C fixed-point cells were constructed and studied in detail using a radiation thermometer and two different thermocouples. Three different furnaces were used to explore the thermal behaviors of the cells at various furnace gradients and furnace offsets. The melting temperature at the inflections point of the melting curves of the cells studied across extensive measurement campaigns demonstrated good performance with repeatability of less than 9 mK (assessed from four successive runs) and reproducibility — less than 100 mK (at different furnaces and furnace offsets). The melting temperature agreement between both cells in the same experimental conditions was better than 30 mK. In addition, the equivalence of the developed large-area cells and a small-area radiometric cell (3 mm cavity aperture, and 35 mm cavity length) were comparatively examined in the same experimental conditions. The coherence of the obtained results for the melting temperature of large-area Fe–C cells indicates the feasibility of using large-volume cells for precise calibration of both radiation thermometers and thermocouples.

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Section: The Point Of Inflection (Poi)mentioning

confidence: 99%

Large-area Fe–C eutectic fixed-points for radiation and contact thermometry

Can,

Gözönünde,

Arifoviç

et al. 2023

Meas. Sci. Technol.

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“…The melting and freezing plateau were realized by applying the furnaces step of +15 K above and −15 K below the melting point of WC-C. The melting points of the WC-C blackbodies was determined as the POI of the melting plateau using the new 'selective multiple fit method' developed at NIM [21]. Using the second derivative of the melting curve, we obtained the The comparison of the large-and small-cell WC-C blackbodies was performed in different three days.…”

Section: Large-area Wc-c Blackbody Temperature Measurementmentioning

confidence: 99%

“…In order to meet the increasing needs for high accuracy calibration of spectral irradiance in various fields in China, a large-area WC-C high temperature fixed-point blackbody system was set up at NIM, which is composed of a 14 mm diameter WC-C cell and a BB3500MP furnace with a radiator inner diameter of 59 mm in 2019 [20,21]. Based on the large area WC-C HTFP, NIM put forwarded a method for spectral irradiance measurement of the FEL lamp in the wavelength from 450 nm to 1000 nm [20].…”

Section: Introductionmentioning

confidence: 99%

“…Based on the large area WC-C HTFP, NIM put forwarded a method for spectral irradiance measurement of the FEL lamp in the wavelength from 450 nm to 1000 nm [20]. Subsequently, in order to improve the measurement uncertainty of spectral irradiance measurement, NIM proposed a selective multiple fit method suitable to calculate the point of infection (POI) of large area HTFP [21], and then adopted Akima fitting method to recover the missing part of the melting plateau curve during spectral irradiance measurement [22]. In 2020, based on the large area HTFP, NIM completed the spectral irradiance scale realization in ultraviolet wavelength from 250 nm to 400 nm and in near infrared wavelength from 1100 nm to 2500 nm.…”

Section: Introductionmentioning

confidence: 99%

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Spectral irradiance scale realization and uncertainty analysis based on a 14 mm diameter WC–C fixed point blackbody from 250 nm to 2500 nm

Dai

Wang

et al. 2022

Metrologia

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Spectral irradiance scale in the wavelength range from 250 nm to 2500 nm was realized at National Institute of Metrology (NIM) on the basis of a large area tungsten carbide–carbon (WC-C) high temperature fixed point blackbody, which is composed of a 14 mm diameter WC-C fixed point cell and a variable temperature blackbody BB3500MP as a furnace. A series of 1000 W FEL tungsten halogen lamps were used as transfer standards. The new spectral irradiance scale was compared with the scale based on a variable-temperature blackbody BB3500M, and the divergence between these two methods varied from -0.66% to 0.79% from 280 nm to 2100 nm. The measurement uncertainty of spectral irradiance scale based on fixed-point blackbody was analyzed, and the expanded uncertainty was estimated as 3.9% at 250 nm, 1.4% at 280 nm, 0.43 % at 400 nm, 0.27% at 800 nm, 0.25% at 1000 nm, 0.62% at 1500 nm, 0.76% at 2000 nm, and 2.4% at 2500 nm respectively. In the range from 300 nm to 1000 nm the fixed-point scale was improved obviously: the uncertainty decreased by more than 25% compared to the uncertainty based on the variable temperature blackbody. Below 300 nm, the uncertainty became higher because the signal to noise ratio was poor. Above 1100 nm, the contribution of temperature measurement to the uncertainty of spectral irradiance decreases, therefore the uncertainties of two methods are almost at the same level. The fixed-point blackbody was also used to realize the correlated colour temperature and distribution temperature of a tungsten filament lamp, the deviation from the variable temperature blackbody method was -0.5 K and -2.9 K, respectively.

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Compilation and evaluation of binary metal (carbide)- carbon phase-transition temperatures

Burgess

2024

AIP Conference Proceedings

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A selective multiple fit method of the point of inflection for the large-area HTFP melting plateau curve

Cited by 3 publications

References 21 publications

Large-area Fe–C eutectic fixed-points for radiation and contact thermometry

Large-area Fe–C eutectic fixed-points for radiation and contact thermometry

Spectral irradiance scale realization and uncertainty analysis based on a 14 mm diameter WC–C fixed point blackbody from 250 nm to 2500 nm

Compilation and evaluation of binary metal (carbide)- carbon phase-transition temperatures

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