| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1999: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Research Abstract |
Calculation of the thermodynamic properties of molten oxides is useful for the development of reining of metals in case that the measurement of properties is experimentally difficult. The molecular dynamics and the molecular simulation are very effective method for the estimation of the properties of gas and liquid phases. The purpose of this study is to establish the estimation method of the thermodynamic properties of ionic solutions by using the molecular dynamics.
In this study, the thermodynamic properties of melts of calcium, oxide and halide mixture such as Ca-CaO-CaF_2 melt were calculated, since these fluxes are used for the purification of metals and the measurement of the thermodynamic properties of these melts is difficult.
The potential function of components such as CaO, CaF_2, CaCl_2, BaO, BaF_2, etc. was investigated for the calculation of molecular dynamics. A lot of potential functions are reported for ionic material. However, the potential function that is suitable for the estimation of all properties is not available. In this study, the Born-Mayer type potential and the soft core potential was applied and the parameters of potentials were determined by comparing the observed melting point of ionic solutions and the calculated one. The Gibbs free energy of the CaO-CaF_2, CaF_2-BaF_2, BaO-BaF_2 systems were calculated by using the potential parameters of compounds and the stability of the systems were discussed. The phase diagrams were obtained from the calculated thermodynamic propertied such as the Gibbs free energy. Furthermore, the activities of components were calculated.
It is shown in this study that the thermodynamic properties of ionic melts can be estimated by the molecular dynamics.
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