| 摘要 |
PURPOSE:To improve purity, strength and light transmission by hot-pressing specific yttria powder to density the powder and subjecting to HIP (hot isostatic pressing) treatment. CONSTITUTION:Yttria powder having >=99.9% purity and 2-10 m<2>/g BET specific surface area is hot-pressed in vacuum under 100-500 kg/cm<2> pressure at 1,300-1,700 deg.C, densified into >=95% theoretical density and subjected to HIP treatment under >=500 kg/cm<2> at 1,400-1,900 deg.C to give light-transmitting sintered material of yttria which comprises a polycrystalline yttria having >=99.9% purity and has >=80% straight-line transmission in 3 mm thickness of specimen in an infrared range at 3-6 mum wavelength, <=100 mum average crystal particle diameter and >=120 MPa 4 points flexural strength. |
