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Your search keyword '"Fukuyama, Hiroyuki"' showing total 13 results
Start Over Author "Fukuyama, Hiroyuki" Journal metallurgical and materials transactions b
13 results on '"Fukuyama, Hiroyuki"'

11. Determination of gibbs energy of formation of cuspidine (3CaO · 2SiO2 · CaF2) from the electromotive force method using CaF2 as the solid electrolyte

Author

Fukuyama, Hiroyuki, Tabata, Hideki, and Nagata, Kazuhiro

Abstract

Abstract: The standard Gibbs energy change for the following reaction has been directly determined by electromotive force (EMF) measurement using CaF2 as the solid electrolyte in the temperature range from 1313 to 1329 K.

$$\begin{gathered} 3CaO \cdot 2SiO_2 \cdot CaF_2 (s) + CaO(s) = 2(2CaO \cdot SiO_2 )(s) + CaF_2 (s) \hfill \\ \Delta _r G^ \circ /kJ = 15.9 - 0.0192T( \pm 0.2) \hfill \\ \end{gathered} $$
From the preceding results, the standard Gibbs energy of formation of cuspidine has been evaluated for the first time as
$$\Delta _f G^ \circ (cuspidine)/kJmol^{ - 1} = - 5198 + 0.825T( \pm 12)$$
The chemical potential diagram for the CaO-SiO2-CaF2 system has been developed at 1323 K based on the thermodynamic data obtained in the present study.

Published
2003
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12. Phase diagram cuspidine (3CaO · 2SiO2 · CaF2)-CaF2

Author

Watanabe, Takashi, Fukuyama, Hiroyuki, Nagata, Kazuhiro, and Susa, Masahiro

Abstract

Abstract: Equilibrium phase diagram for the system cuspidine (3CaO · 2SiO2 · CaF2)-CaF2 has been studied by the quenching method and differential thermal analysis (DTA). Hermetically closed platinum capsules were used in both methods to prevent fluorine loss in the form of HF and SiF4 by reaction of the CaF2 with water vapor or SiO2. Cuspidine congruently melts at 1680±2 K. The cuspidine-CaF2 system presents a simple eutectic type of phase diagram. The eutectic composition and temperature are 46 mass pct 3CaO · 2SiO2−54 mass pct CaF2 and 1515±3 K, respectively.

Published
2000
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13. Phase diagram for the system CaO-Al2O3-ZrO2

Author

Murakami, Taichi, Fukuyama, Hiroyuki, Nagata, Kazuhiro, Susa, Masahiro, and Kishida, Tsunechika

Abstract

Abstract: Phase equilibria in the system CaO-Al2O3-ZrO2 were studied to optimize nozzle composition for tundishes that are used in continuous casters of steel, by identifying the composition that minimizes clogging. Mixtures of CaO, Al2O3, and ZrO2 with various compositions were equilibrated at 1873 and 1773 K and then quenched into water. X-ray diffraction analysis was used for phase identification, and electron probe microanalysis was employed to measure chemical compositions. On the basis of these and previous results, the eutectic and peritectic lines have been estimated. Based on the phase diagram, the optimal nozzle composition is CaO-saturated CaZrO3.

Published
2000
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