The effect of the eutectic structure and the residual effect of impurities on the uncertainty in the eutectic temperatures of Fe–C and Co–C

Bloembergen, P.; Yamada, Yoshiro; Sasajima, N.; Wang, Y; Wang, T

doi:10.1088/0026-1394/44/5/004

Cited by 36 publications

(86 citation statements)

References 18 publications

(48 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the further course of the measurements, the emfs of the freezes gradually decreased but with a tendency to become stable. The literature [4,11,12] confirms that the freezing temperature of Fe-C is sensitive to the freezing offset temperature. The difference we obtained between the melting and freezing temperatures in this work is very close to the results of previous work on a graphite Fe-C cell [4].…”

Section: Methodsmentioning

confidence: 81%

Realization of Fe–C Eutectic Point Using an Alumina Crucible

2010

View full text Add to dashboard Cite

As another crucible material for metal-carbon eutectic points, alumina ceramic was used in the first trial to make an Fe-C eutectic point for the calibration of a thermocouple. Its melting and freezing behavior was tested 26 times with a type S thermocouple at various melting offset temperatures, namely, +4 • C, +9 • C, and +19 • C, and at a fixed freezing offset temperature of −11 • C. The melting emf is reproducible independent of the melting offset temperatures, and the standard deviation of the 26 melting temperatures is 0.02 • C without breakage of the cell. The difference of melting emf between alumina Fe-C and graphite Fe-C fixed points is only 25 mK within an uncertainty of 0.39 • C (k = 2). The melting behaviors of an alumina cell are quite similar to a common graphite cell. Thus, alumina can be used as a crucible material in an Fe-C eutectic system without breakage, and it can be used at a higher temperature range. As possible application systems using alumina crucibles, Pd-C and Si-SiC eutectic points are suggested.

show abstract

Section: Methodsmentioning

confidence: 81%

Realization of Fe–C Eutectic Point Using an Alumina Crucible

2010

View full text Add to dashboard Cite

show abstract

“…Note that these uncertainties do not include the uncertainty associated with the cell itself, such as those arising from impurities in the eutectic [14], from emissivity of the cell within the furnace environment [15], from the definition of the point of inflection, etc. These concerns are being considered within work package 3 of the The uncertainty associated with the radiometric measurement is given, expressed as a temperature; note that this does not include the uncertainties associated with the cell properties (impurities, furnace effects, emissivity, etc.)…”

Section: Uncertainty Associated With Measurements Of Fixed Pointsmentioning

confidence: 99%

Primary Radiometry for the Mise-en-Pratique for the Definition of the Kelvin: The Hybrid Method

et al. 2011

View full text Add to dashboard Cite

A task group of CCT-WG5 (radiation thermometry) was established in May 2008 to write text for the mise-en-pratique for the definition of the kelvin (MeP-K) for high temperatures. This task group reviewed and gave summaries for the existing techniques for filter radiometry as a means of determining the absolute radiance, and hence the thermodynamic temperature of a blackbody source. Three approaches were described-the radiance method, which calibrates the radiation thermometer for radiance responsivity, the irradiance method, which calibrates a filter radiometer for irradiance responsivity and then measures the source through two apertures, and the hybrid method that introduces a lens to the irradiance method. In the "hybrid method" the radiation thermometer consists of a filter radiometer, a double aperture system, and a lens. The lens allows the instrument to view a small area blackbody source. The system is calibrated "in parts"-i.e., the filter radiometer is calibrated for irradiance responsivity, and the transmittance of the lens and the geometric factor are determined separately. The main drawbacks of this single lens instrument are its high size-of-source effect (∼0.2 %), and that this effect has to be determined in an "absolute" sense-relative to a theoretical infinite source. However, although the correction is large, with careful evaluation, the associated uncertainty can be made sufficiently small to measure the temperature of fixed-point cell transitions with low uncertainties. This article reviews the hybrid method and gives a comprehensive discussion of the associated uncertainty components.

show abstract

“…The liquidus temperatureT liq,melt , related to melting, was obtained by a procedure described earlier for the eutectic Fe-C and Co-C [9]. As shown in Fig.…”

Section: Melting Experimentsmentioning

confidence: 99%

“…However, the metal carbon eutectic's melting temperature has been found to be more reproducible than the freezing temperature since it is less susceptible to the rate of the associated freeze than the freezing temperature itself [5][6][7]. For eutectic systems, the effect of the rate of the freeze on the phase-transition process has been related to the two-phase eutectic microstructure in conjunction with impurities [8,9].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

On the Freezing and Melting Behavior of the Eutectic Pt–C

et al. 2011

View full text Add to dashboard Cite

The feasibility of referring to freezing as an alternative to melting for defining the eutectic transition temperature has been studied using two Pt-C cells constructed at NIM, one of a sleeve type, and the other of a hybrid type, including support. Freezing and melting experiments have been done by varying the offset of the furnace temperature T furn with respect to the nominal eutectic temperature T E used to freeze the fixed point with offsets (T furn − T E ) freeze from −5 K to −40 K, followed by melting at a fixed offset (T furn − T E ) melt = +20 K. Plotting the liquidus temperatures T liq,freeze and T liq,melt obtained for freezing and melting against (T E − T furn ) 1/2 freeze resulted in linear relations for both cells, allowing extrapolation toward T liq,freeze (0) and T liq,melt (0). For the cells Pt-C5# and Pt-C6# under study: T liq,melt (0) − T liq,freeze (0) = 10 mK and 20 mK, respectively, with a standard uncertainty of 30 mK for both T liq,melt (0) and T liq,freeze (0). The coherence of the results obtained for melting and freezing indicates that freezing can be used, as an alternative to melting, to define the liquidus temperature T liq (0) of the eutectic Pt-C.

show abstract

The effect of the eutectic structure and the residual effect of impurities on the uncertainty in the eutectic temperatures of Fe–C and Co–C

Cited by 36 publications

References 18 publications

Realization of Fe–C Eutectic Point Using an Alumina Crucible

Realization of Fe–C Eutectic Point Using an Alumina Crucible

Primary Radiometry for the Mise-en-Pratique for the Definition of the Kelvin: The Hybrid Method

On the Freezing and Melting Behavior of the Eutectic Pt–C

Contact Info

Product

Resources

About