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Hayashi, Takeru*; Nishi, Tsuyoshi*; Ota, Hiromichi*; Hatori, Kimihito*; Awano, Takaaki*; Igarashi, Takahiro; Koshina, Takafumi*
no journal, ,
In order to establish deterioration diagnosis technology for surface coating materials, we examined the measurement method and analysis method. The local thermal diffusivity could be measured by the laser spot periodic heating radiation thermometry method. In addition, it was also measured the thermal diffusivity by the xenon flash method to compare that by the laser spot periodic heating radiation thermometry method. A two-layer analytical formula was constructed for the coating sample, because there is a possibility that single-layer analysis may not give accurate results. As a result of measurement at room temperature, the thermal diffusivity decreased remarkably in the thickness direction measurement when the coating surface was placed on the detection surface side. On the other hand, the thermal diffusivity kept remained when the coating surface was placed on the heating surface side.
C alloyKokubo, Hiroki*; Nishi, Tsuyoshi*; Ota, Hiromichi*; Takatsuka, Yuriko*; Yamano, Hidemasa
no journal, ,
The measurements of the viscosities of molten alloys at elevated temperatures is complex owing to the difficulty in handling low viscosity fluids such as SS-BC alloy. In this study, the viscosity of molten nickel (Ni) and stainless steel (SS) were measured using an oscillating crucible method to validate the performance of the viscosity measurement apparatus. This method is suitable for high-temperature molten alloys. A crucible containing molten metal was suspended, and a rotational oscillation was provided to the crucible electromagnetically. The friction of molten metal dampens the oscillation. The viscosity was determined from the period of oscillation and logarithmic decrement. The crucible was connected to a mirror block and an inertia disk made of aluminum, and then, suspended by a wire made of platinum-13% rhodium alloy. Laser light was used to irradiate the mirror. The reflection light was detected using photodetectors, and then, the logarithmic decrement of molten metal was determined. The viscosities of molten Ni and SS melts were measured up to 1823 K. From these results, the measured viscosity values of molten Ni and SS were found to be close to their literature values. The viscosity of molten SS-BC was determined in this study. However, BC composition dependence on the viscosity of molten SS-BC alloy is yet to be clarified.