To obtain crystal grains having texture or random direction, by filling a capsule can with material powder, and isotropically hot-pressing the powder after degassing and tight sealing.
Raw material is stoichiometrically weighed, sealed in a quartz tube or the like, melted and cooled, and the obtained ingot pulverized. A capsule can is filled with the mixed powder. After degassing and tight sealing, HIP is performed by using Ar gas as pressure medium. The density ratio designates the ratio of the density of a sintered article to the density of a perfect dense body. Since the capsule can is pressurized with a gas pressure having isotropy, the compressive force can be applied to the interior of the can. Thereby it can be unnecessary to increase the treatment temperature of the treatment period, when the product size is large. Hence a product of high density can be obtained without enlarging crystal grains. The crystal grains of an obtained sintered article have a texture of random direction, and the bending strength has no anisotropy. Thereby, when slice-working is performed, fracture and cutout are not generated in a slice-worked article.
KAGAWA SHUZO
SATAKE HIDEKI
Next Patent: SUPERCONDUCTING CURRENT LIMITING DEVICE