| 摘要 |
Because fracture toughness and translucency of translucent colored alumina sintered body of the past were low, the alumina sintered body was not suitable for uses such as dental materials, which require high toughness. The present invention relates to providing a translucent colored alumina sintered body that contains transition metal oxides, and with which the fracture toughness is 4.5 MPa·m0.5 or more and the maximum value of total forward transmittance (sample thickness 1 mm) to a wavelength of 300-800 nm is 60% or more. The present invention relates to obtaining a sintered body, at least 20% of which contains anisotropic grains with a long axis length of 10μm or greater and an aspect ratio of 1.5 or more by subjecting an alumina sintered body containing transition metal oxides having a eutectic point with alumina or an alumina sintered body containing transitional metal oxides and at least one selected from the group consisting of Group 1A alkali metal oxides, Group 2A alkaline earth metal oxides, and SiO2, B2O3, P2O5 and GeO2 to pressureless sintering and HIP treatment.
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