Tokyo Institute of Technology · Materials Science
Professor Manabu Watanabe's research lab specializes in the thermophysical properties of molten metals and alloys, with a focus on high-precision measurements of density, surface tension, viscosity, and thermal conductivity using electromagnetic and electrostatic levitation techniques under controlled magnetic fields. The lab investigates the relationships between thermodynamic functions, excess molar properties, and phase transitions—particularly order–disorder transitions—in binary and multicomponent alloy systems such as Pt–X, Co–Cr–Mo, and Au–X. Their work supports advanced materials processing, especially in additive manufacturing and biomedical implant development, by providing critical data for process modeling and optimization. The lab also explores nanofabrication techniques, such as AFM-based nanowire synthesis, and surface phenomena in micro/nanofabrication processes like resist development in semiconductor manufacturing.
Figures are computed from collected data and may differ slightly.
The densities of liquid binary Pt–X (X: Fe, Co, Ni and Cu) alloys were measured over a wide temperature range including the supercooled liquid region, using electromagnetic levitation under a static magnetic field. The static magnetic field effectively suppressed translational motion and surface oscillation of the levitated Pt–X sample droplets, enabling high-accuracy density measurement in a non-contact manner. The excess molar volumes (VE) of the liquid alloys were evaluated from the density m
This study aimed to provide thermophysical property data of Co–Cr–Mo (CCM) alloys that are used as biomedical materials to understand and improve additive manufacturing processes. The density, surface tension, normal spectral emissivity, specific heat capacity and thermal conductivity of two CCM alloys that contained a low (0.053 mass%) and a high (0.251 mass%) carbon content were measured in a liquid state using an electromagnetic levitation technique. The liquidus temperatures of the CCM alloy
Our group has previously investigated the correlations between the excess volumes, thermodynamic functions and phase diagrams of binary alloy melts, and the present study focused on binary Au-X (X = Cu, Pd and Ni) alloy melts. The Au-Cu and Au-Pd systems have intermetallic compounds with order–disorder transitions. The densities of these alloy melts were determined with small uncertainties using a combination of an electromagnetic levitation technique and a static magnetic field. The densities o
Co-Cr-Mo (CCM) alloys, which are used in biomedical implants, are currently produced by additive manufacturing, for which accurate modeling of the process is required to attain the desired thermophysical properties of the melts. For the purpose of modeling, the density, surface tension, and viscosity of two CCM melts of distinct carbon content (0.05 and 0.25% by mass) were measured using an electrostatic levitation technique. The temperature dependence of both density and surface tension of the
In this study, we investigated resist pattern collapse during the resist development process. We evaluated the effect of a simple improvement such as rinse-liquid sequencing and rinsing using surfactants. First, we controlled the wafer spinning speed during the rinse-liquid flow step to reduce liquid flow shock. Using this approach, we obtained a 110-nm L/S (line and space) structure with no pattern collapse. However, this technique has only a small effect on preventing pattern collapse with sub
Gold nanowires were fabricated using a contact mode atomic force microscope (AFM), the tip of which scans a thin gold layer predeposited on a mica substrate. The nanowires are spaced with an interval in the range of 130–590 nm. Their widths and heights are distributed in the range of 70–110 nm and 4–7 nm, respectively. By adjusting the strength of the force applied by the AFM tip, the spacing, width and height of the nanowires can be controlled and made to increase as the applied force increases
Abstract This study aimed to accurately measure the density ( ρ ), normal spectral emissivity ( ε ), heat capacity at constant pressure ( C p ), and thermal conductivity ( κ ) of the Ti–6 mass % Al–4 mass % V (Ti64) melt by electromagnetic levitation with a static magnetic field and laser modulation calorimetry. A static magnetic field was applied to the levitated Ti64 melt to suppress the surface oscillation and translational motion of the droplets, and to suppress the convection flow inside th
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