An Effect of Transfer Velocity on Formation of Porous Alumina during Unidirectional Solidification

摘要

An effect of transfer velocity on the formation of porous alumina during the unidirectional solidification under pressurized 50%H_2-50%Ar mixed gas was examined. The porosity of the samples increases with the transfer velocity up to 400 mm/h (111 μm/s) and then, it gradually decreases. The pore morphology such as positional distribution in the samples and pore direction against solidification direction varies with the transfer velocity. When the transfer velocity is 400 mm/h, the sample with a maximum porosity was obtained where the angle between solidification direction and pore direction is zero. The angle between solidification direction and pore direction increases with the transfer velocity.