Establishment of prediction formula for diffusion coefficient in liquid metals

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04990
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26010:Metallic material properties-related
• Research Institution: Waseda University
• Principal Investigator: Suzuki Shinsuke 早稲田大学, 理工学術院, 教授 (10437345)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 拡散係数 / 液体金属 / 自己拡散 / 不純物拡散 / 固有拡散 / 相互拡散 / 原子半径比 / 熱力学因子

Outline of Final Research Achievements

Diffusion experiments were performed by the shear cell method and stable density layering with suppressing convection for the purpose of establishing a precise prediction formula for diffusion coefficient in liquid metal. The main findings are as follows. The temperature dependence of the atomic radius can be obtained from the Protopapas equation, molar volume, and scattering diffraction experiments. The atomic radius ratio of the solvent to the solute can be used to calculate the impurity diffusion coefficient. In the range of the atomic radius ratio of the solvent to the solute less than about 1 near the melting point of the solvent, the impurity diffusion coefficient can be estimated by multiplying the self-diffusion coefficient of the solvent by the atomic radius ratio and the atomic weight ratio to the n-th power (n=0.119 for Sn liquid). In the range of the atomic radius ratio larger than this, it can be predicted to be equivalent to the self-diffusion coefficient of the solvent.

Free Research Field

金属の高温融体物性，溶融・凝固，塑性変形

Academic Significance and Societal Importance of the Research Achievements

本研究で得られた不純物拡散係数の予測手法を、今後、他の実用合金に適用することにより、凝固・結晶成長のシミュレーションの精度向上が期待できる。これにより、合金開発、プロセス開発を大幅に改善し、金属製品を高機能化・高性能化できる。本研究の実験データを適用すれば、MDシミュレーションの精度も向上する。これらの成果により、粘性係数など他の輸送係数の研究も、本研究成果を利用して発展させることができる。液体の構造とダイナミクスの理論構築への新展開へも貢献できる。