1992 Fiscal Year Final Research Report Summary
Thermodynamic Study of Ca in Liquid Iron
| Project/Area Number |
03453063
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
金属精錬・金属化学
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
ICHISE Eiji Kyoto Univ. Fac. Eng. Professor, 工学部, 教授 (10025918)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIWARA Hiroyasu Kyoto Univ. Fac. Eng. Instructor, 工学部, 助手 (10238602)
MORO-OKA Akira Kyoto Univ. Fac. Eng. Lecturer, 工学部, 講師 (20026008)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Thermodynamics of Fe-Ca-O system / Solubility product of CaO / Activity coeficient of Ca / Ca-O interaction / Determination of Low conc. Ca / Bulk analysis by SIMS |
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| Research Abstract |
Thermodynamic behavior of the liquid Fe-Ca-O alloy in equilibrium with CaO was studied.
Liquid iron in a CaO crucible was placed in a closed Ta container together with liquid Ca-Ag alloy or CaOsat.-FeO liquid slag and all these phases were brought to equilibrium at 1823K and quenched then metallic phases were analyzed for Ca and O. The following results were obtained. A value of 270ppm is obtained for the solubility of Ca in liquid iron in equilibrium with CaO at 1823K where the activity of Ca is 0.85. The activity coefficient of Ca does not depend on the Ca concentration in the composition range from 1 to 270 ppmCa and its value is given by In gamma Ca = 7.8+0.7. The concentration of O in equilibrium with CaO is almost constant at 8+2ppm in the Ca concentration range from 1 to 270ppm.
The possibility of applying the Secondary Ion Mass Spectrometric analysis to the determination of bulk Ca of low concentration was studied and the following results were obtained. Using Oxygen as the primary ion, taking sweep area 500um square and acquisition area 150um square and measuring over 10 spots each sample, one can obtain less than 10 % for the relative standard deviation of the relative ion intensity of Ca. Analysis by the use of SIMS of Fe-Ca alloys of several to several hundred ppmCa which is determined by wet analysis, a Ca standard sample for instrumental analysis and a Ca ion doped iron sample gave a good linear corelation between relative Ca ion intensity and bulk Ca concentration which may be used as the calibration line for the determination of Ca in a Fe-Ca alloy by the use of SIMS. Some points on the analysis of Ca ion doped sample were studied.
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