Properties of black Y2O3 sintered bodies

Black Y₂O₃ pieces are obtained by heating in a reducing atmosphere, and they have some properties other types of Y₂O₃ do not have. In this study, hardness, transmittance and thermoluminescence of black Y₂O₃ sintered pieces are investigated.The Knoop hardness numbers of the black Y₂O₃ pieces vary from 615 to 804 kg/mm², and the average hardness number is 699 kg/mm², which is nearly equal to that of a colorless piece. In-line transmittances of the dark Y₂O₃ pieces in the 0.2～11 μm wavelength are lower than those of colorless pieces. The trap level of the black Y₂O₃ pieces is 1.22 eV.