| 摘要 |
PURPOSE:To promote high-density formation and to improve light transmission as infrared light transmitting window in sintering magnesia-alumina spinel, by introducing a high-pressure gas to a furnace. CONSTITUTION:High-purity and fine magnesia-alumina spinel power having >=99.9% purity and >=10m<2>/g (BET value) specific surface area is molded under >=1.0ton/cm<2> static pressure to give a molded article having >=2.0 specific gravity of molding. Then the molded article is sintered in multiple stages in vacuum or hydrogen or helium atmosphere at 1,400-1,800 deg.C for 2-24hours and made into high density of >=95% theoretical density. Then a high-temperature nitrogen gas, argon gas or helium gas under 10-150kg/cm<2> pressure is introduced into a furnace, the molded article is further made into high density to give a light- transmitting spinel sintered material. The magnesium-alumina spinel sintered material has >=75% straight-line percent transmission in 2mm thickness by infrared light at 3-4mum wavelength. |
