Realization of Fe–C Eutectic Point Using an Alumina Crucible

Kim, Y.-G.; Gam, Kee Sool; Yang, Inseok

doi:10.1007/s10765-010-0783-z

Cited by 7 publications

(5 citation statements)

References 11 publications

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“…If the weak mechanical resistance of alumina at high temperature is overcome, the Si-SiC eutectic point in an alumina crucible can be useful in thermometry, especially for the calibration of thermocouples. Present studies on making metal-carbon cells using an alumina crucible are going on at our laboratory [15]. Based on this result, we made a Si-SiC cell for thermocouple thermometry and evaluated its melting and freezing behaviour using a Pt/Pd thermocouple.…”

Section: Resultsmentioning

confidence: 99%

Study on the melting and freezing behaviour of high temperature binary eutectic fixed points using differential scanning calorimetry

Kwon¹,

Kim²,

Yang³

2010

Metrologia

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We have measured the heat flux accompanying the melting or freezing of metal (or metalloid)–carbon eutectics, using differential scanning calorimetry (DSC) to identify appropriate binary systems for secondary thermometry fixed points. Well-known alloy systems such as Fe–C and Ni–C showed reproducible endothermic and exothermic peaks that represent melting and freezing reactions in the DSC measurement. Furthermore, a new Si–C system with a eutectic composition showed reproducible melting and freezing peaks in the DSC measurements. Based on the results by DSC, we identified the Si–SiC eutectic point as a possible eutectic fixed point. To confirm this possibility, we made a Si–SiC cell for thermocouple thermometry and measured its melting and freezing characteristics using a Pt/Pd thermocouple. The melting temperature of the Si–SiC eutectic was reproducible to within 0.02 °C (one standard deviation). From the results, we found that Si–SiC has possibility as a new eutectic fixed point at temperatures around 1400 °C. We also concluded that DSC analysis could be used to measure the reproducibility of freezing and melting reactions that are to be used as fixed points for thermometry, because it is a rapid and easy-to-use tool for characterizing the thermal behaviour of materials with only a small sample.

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Section: Resultsmentioning

confidence: 99%

Study on the melting and freezing behaviour of high temperature binary eutectic fixed points using differential scanning calorimetry

Kwon¹,

Kim²,

Yang³

2010

Metrologia

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“…The Fe-C eutectic fixed-point temperature [7,8] is expected to be 1153 • C, which is close to the copper point but nevertheless provides a convenient supplementary calibration point. In particular, Fe-C eutectic fixed-point cells are important for the nuclear industry since they are expected to be significantly more stable under irradiating/ionizing conditions than either copper or Co-C because the small neutron capture cross-section of iron results in a low transmutation rate [9].…”

Section: Introductionmentioning

confidence: 98%

Fe–C eutectic fixed-point cells for contact thermometry: an investigation and comparison

et al. 2011

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Five iron–carbon (Fe–C) eutectic fixed-point cells have been constructed between NPL and LNE-Cnam to investigate the robustness and to measure the agreement of their melting temperatures. Each cell was constructed with a different selection of materials sourced by NPL and LNE-Cnam. The measured emfs at the Fe–C fixed-point temperature (∼1153 °C), compared between cells, agree within around 1.98 µV (∼90 mK), where the most important contribution to the uncertainty of each measurement is the inhomogeneity associated with the measuring Pt/Pd thermocouple. This demonstrates that these cells are suitable for use as secondary fixed-point cells in contact thermometry but the robustness of the presented cells is not found to be sufficient for maintaining their integrity during repeated cycling procedures.

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“…The small difference in cell volume between the cells was due to the machining tolerance variation of the ceramic materials. An electric high-temperature furnace with six vertical U-shaped Kanthal super heaters was used [4,9,12,13]. To protect the Fe sample from oxidation at high temperature, a mixture of Ar (99.999% purity) and 0.5 vol% hydrogen continuously flowed into the cell during all experiments.…”

Section: Methodsmentioning

confidence: 99%

“…Consequently, alumina ceramic was selected as a possible solution. It has been reported that Fe-C [9], Ni [10], Ni-Ag [11] and Pd [12] cells were successfully fabricated using alumina crucibles without breakage after successive melting and freezing cycles. Thus, Fe cells were made using alumina crucibles.…”

Section: Introductionmentioning

confidence: 99%

Phase transition behavior of pure Fe cells for thermocouple calibration

Kim¹,

Kwon²,

Kim³

2022

Metrologia

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The fixed points adopted in the ITS-90 have generally been used to calibrate contact thermometers, such as thermocouples, to get the highest accuracy. The fixed point for Pd is located at the upper limit range of the Pt/Rh noble metal thermocouple calibration. However, the high price of Pd itself restricts its wide use in calibration laboratories. To overcome this difficulty, this study develops an alternative fixed point having a close transition temperature to the Pd freezing temperature of 1554.8 °C. The alternative is pure Fe with a quoted melting temperature of 1538 °C. To make a thermometric cell, an alumina crucible was used to contain the molten liquid and it was found to be robust enough to last for more than 60 cycles of melting and freezing tests without any chemical and mechanical damage. Two cells were fabricated, and their melting and freezing behaviors were studied using type B thermocouples. By considering the advantage and disadvantages of melting and freezing, the melting temperature was selected as a thermometric transition point for the calibration of thermocouples because of its easy operational processes and acceptable uncertainty level. Using a reference thermocouple that had been calibrated versus a standard radiation thermometer, the average melting temperature of the two Fe cells was 1534.0 °C with an uncertainty of 1.2 °C (k = 2). From the studies, an Fe cell made in an alumina crucible can successfully replace the Pd fixed point.

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Realization of Fe–C Eutectic Point Using an Alumina Crucible

Cited by 7 publications

References 11 publications

Study on the melting and freezing behaviour of high temperature binary eutectic fixed points using differential scanning calorimetry

Study on the melting and freezing behaviour of high temperature binary eutectic fixed points using differential scanning calorimetry

Fe–C eutectic fixed-point cells for contact thermometry: an investigation and comparison

Phase transition behavior of pure Fe cells for thermocouple calibration

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