Search

著者人数: 15名, Accepted: 2020-02-11, 資料番号: SA1190184000

Accepted: 2015-12-15, 資料番号: SA1160353000

Crystal–liquid interfacial free energy is important to understand in crystal study, for example, nucleation, crystal growth, and vitrification. Here, we report the nanosized nucleus-supercooled liquid interfacial free energy of early and late transition liquid metals using the electrostatic levitation (ESL) technique and classical homogeneous nucleation theory (CNT). For the estimation of the interfacial free energy, we obtained thermophysical parameters of the transition liquid metals (Ti, Fe, Ni, Zr, Nb, Rh, and Hf), such as hypercooling limit (ΔThyp), specific heat (Cp), total hemispherical emissivity (eT), and density (ρ). The estimated interfacial free energies of Ti, Ni, and Zr agreed well with a previous report having similar hypercooling limit and fusion enthalpy, while Fe, Nb, Rh, and Hf show different values from the report. This reflects the importance of accurate measurement of the two quantities. The obtained Turnbull’s coefficients (α) of the liquid metals is higher than 0.45. The interfacia...

Electrostatic levitators have been around for more than 30 years and have become mature tools for the material science community. Originally developed as positioners for materials and fluid science experiments in space, they saw a myriad of offsprings throughout the world for ground-based research, not only in space agencies but also in governmental laboratories, in universities and in the industry. Electrostatic levitators eliminate any physical contact with a container allowing to process and study corrosive or high temperature materials in their solid or liquid phases. Moreover, heterogeneous contamination from the container being avoided, it is possible to reach and maintain supercooled and metastable phases. This, in turns, permits a host of fundamental and applied studies. The nucleation and solidification phenomena can be scrutinized, the atomic structure and dynamic of liquid and metastable phases can be probed and the physics of molten drops could be investigated. On a more applied standpoint, the measure of thermophysical properties and the synthesis of materials with new properties are also possible with current facilities. This paper first describes the principle of electrostatic levitation and retraces the development of various facilities throughout the world, focusing on the advances made by each research group. The capabilities of electrostatic levitation for materials processing and synthesis under different environments are then presented. The paper successively covers in length its contribution for the measurements of thermophysical properties and for fundamental studies using high energy particle beams. Finally, the outlook of electrostatic levitators and its attractiveness for space experiments in materials sciences are discussed.

Accepted: 2012-11-15, 資料番号: SA1004278000

高温融体内の原子の運動に関する実験的な知見は、融体の熱物性と構造の関係を理解する上で極めて重要である。我々は、高温融液の原子ダイナミクスの観察を目的として非弾性X線散乱用の小型の静電浮遊装置を開発し、融点および過冷却液体シリコンの動的構造因子を測定した。本装置を用いることにより液体シリコンのフォノンピークが明瞭に観察され、その分散関係が明らかになった。, The atomic dynamics in high temperature melts are essential information for the understanding of the relation between liquid structure and thermo-physical properties in liquid state. The small Electrostatic Levitation furnace, ESL, was developed for the inelastic X-ray scattering facility in SPring-8. The observation of dynamic liquid structure factor, S (Q, w) of normal and undercooled liquid silicon was performed. The phonon peak of S (Q, w) in the liquid silicon was clearly observed and its dispersion relation can be obtained., 資料番号: AA0063323004, レポート番号: JAXA-RR-06-015E

The atomic dynamics in high temperature melts are essential information for the understanding of the relation between liquid structure and thermo-physical properties in liquid state. The small Electrostatic Levitation furnace, ESL, was developed for the inelastic X-ray scattering facility in SPring-8. The observation of dynamic liquid structure factor, S(Q,w) of normal and undercooled liquid silicon was performed. The phonon peak of S(Q,w) in the liquid silicon was clearly observed and its dispersion relation can be obtained., 資料番号: AA0063349039

Accepted: 2013-05-01, 資料番号: SA1004492000