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Accepted: 2018-12-01, 資料番号: SA1180327000

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

This review briefl y describes the vacuum electrostatic levitation furnace developed by JAXA and the associated non-contact techniques used to measure the density, the surface tension and the viscosity of materials. The paper then presents a summary of the data taken with this facility in the equilibrium liquid and non-equilibrium liquid phases for the six platinum group metals (pgms): platinum, palladium, rhodium, iridium, ruthenium and osmium over wide temperature ranges that include undercooled and superheated phases. The presented data (density, surface tension and viscosity of Pt, Rh, Ir, Ru and Os and density of Pd) are compared with literature values.

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...

Short duration microgravity experiments are useful tools for the development of experimental apparatus for microgravity researches. Parabolic flights have been frequently used for the development of the electrostatic levitation furnace (ELF) for the International Space Station (ISS). The history of ELF development and parabolic flight experiments conducted for its development are briefly described in this paper., 形態: 図版あり, Physical characteristics: Original contains illustrations, 資料番号: DS1440102000

Viscosities of tungsten, rhenium, osmium, tantalum, and molybdenum have been measured by the oscillation drop method with an improved procedure. The measured data exhibit less-scatter than our previous measurements. Viscosity at the melting temperature of the investigated metals showed a good agreement with literature values and some predicted values.

Accepted: 2010-02-07, 資料番号: SA1000813000

Electrostatic levitators use strong electric fields to levitate and accurately position a sample against gravity. In this study, the effects of the electric field are investigated with regards to viscosity measurements conducted with the oscillating drop method. The effects of the external field on viscosity measurements are experimentally confirmed by changing the sample size. Moreover, a numerical simulation based on a simple mass-spring-damper system can reproduce the experimentally observed effects. Based on the above results, measurement procedures were improved. These help to minimize the effect of the positioning force and increase the accuracy of the viscosity measurements., 資料番号: AA0064541000, レポート番号: JAXA-RR-09-002E

Thermophysical properties of four rare earth elements, namely Lanthanum (La), Praseodymium (Pr), Neodymium (Nd), and Terbium (Tb) have been measured using electrostatic levitation techniques. The understanding of the nature and behavior of rare earth metals in their liquid phases requires accurate values of their physical properties. However, keeping samples in their liquid phases free from contamination long enough to carry out measurements represents a formidable challenge. This is due to high reactivity and melts contamination of these elements with crucibles or gaseous environment. The use of an electrostatic levitator in vacuum conditions circumvents these difficulties and permits the measurements of the density, the surface tension, and the viscosity of these metals above and below their melting temperature. In this paper, the measurement methods as well as the levitation apparatus are introduced and measured values are reported., 資料番号: AA0063800000, レポート番号: JAXA-RR-07-014E

資料番号: PAIS08104000

An electrostatic levitator was developed for the structural analysis of high-temperature and undercooled liquids by X-ray diffraction. The apparatus can be used to investigate the structure of metallic, semiconductor, and ceramic liquids. Samples of zirconium, silicon, and alumina in their liquid phases could be kept levitated for more than one hour with this apparatus. This was sufficiently long to perform a detailed analysis of the liquid structure by X-ray diffraction techniques., 資料番号: AA0063323003, レポート番号: JAXA-RR-06-015E

Accepted: 2006-02-23, 資料番号: SA1000066000

資料番号: SA1000026000

Accepted: 2005-11-23, 資料番号: SA1000507000

The containerless technique is one of the latest methods for the handling of matters at high temperature and in undercooled liquid states. In this research project, the electrostatic levitation technique has been applied to the structural analysis of liquids by using the neutron and X-ray scattering techniques. The current status of this subject is described briefly., 資料番号: AA0048709004, レポート番号: JAXA-RR-04-044E

Thermophysical properties of molten refractory metals, whose melting temperatures are over 3,000 degrees C, have been measured using an electrostatic levitation furnace. The modified electrodes increased the sample position stability so that non-contact thermophysical properties measurement techniques could be implemented. Properties such as density, surface tension, and viscosity of tantalum, rhenium, and tungsten have been measured over wide temperature ranges, including the undercooled region., 資料番号: AA0048095010

Accepted: 2004-09-13, 資料番号: SA1002364000

Accepted: 2003-02-07, 資料番号: SA1002374000

Some thermophysical properties of liquid and supercooled palladium were measured using containerless techniques. Over the 1640–1875 K temperature interval, the density could be expressed as ρ(T)=10.66× 103 −0.77(T−Tm)(kg·m−3) and the ratio between the isobaric heat capacity and the hemispherical total emissivity could be rendered as (J·mol−1·K−1), where T m =1828 K. The volume expansion coefficient was also determined as 7.2 × 10−5 K−1.

Pure Si samples with diameters of about 1.7 mm were undercooled down to 317 K while electrostatically levitated. The crystal growth velocities were measured as a function of undercooling and the appearance of the solid/liquid interface was observed by means of a high-speed camera. The results were compared with those reported previously for larger Si droplets using an electromagnetic levitator. In this study, nucleation was triggered at a given undercooling using needle darting and particle interspersing. As a new finding, the transition of growth mechanism from a single plate to multi-plate crystal was observed at the undercooling of 80 K. Transitions from plate-like crystal to coarse faceted dendrite and from coarse to fine faceted dendrite hardly depended on the sample size.

Thermophysical properties of molten refractory metals have been measured using an electrostatic levitation furnace. The developed levitation furnace could stably levitate molten samples at temperatures exceeding 3,000 C. In addition, non-contact thermophysical properties measurement techniques have been implemented. Properties such as density, heat capacity, heat of fusion, surface tension, and viscosity have been measured over wide temperature ranges, including the undercooled region., 資料番号: AA0046917081

Accepted: 2003-10-31, 資料番号: SA1002382000

Accepted: 2004-07-09, 資料番号: SA1002383000

Accepted: 2003-02-12, 資料番号: SA1002373000

Accepted: 2003-02-05, 資料番号: SA1002371000

Accepted: 2002-11-19, 資料番号: SA1002370000

This article describes an aerodynamic levitation system for the processing and study of undercooled insulator materials by drop tube and quenching experiments. Its operation principle relies on a convergent-divergent type aerodynamic levitator made of two halves that can be quickly separated along a plane collinear with gas flow through the action of air-actuated pistons. This article reports the concept of this new levitator and presents the proof of the technical feasibility of contactlessly melting, undercooling, and accurately free falling alumina samples. Short duration microgravity conditions could therefore be accessed with this system for a superheated or undercooled insulator sample. In addition, sample behavior in terms of position stability and rotation was investigated. It was found that tilt of the diffuser permitted sample rotation control. Moreover, experiments showed promise for the control of the cooling rate and the selection of the temperature at which quenching occurs due to the additi...