PRODUCTION OF LIGHT-TRANSMITTING SPINEL CALCINED COMPACT

摘要

PURPOSE:To obtain a light-transmitting spinel suitable as an infrared ray transmitting window material used within an infrared region by hot-pressing a spinel powder having a specified purity and specific surface area in two stages. CONSTITUTION:A spinel powder of >=99.9% purity (especially a transition metal such as Fe, is not preferred) and >=10m<2>/g specific surface area (BET value) is hot-pressed at 1300-1500 deg.C under 100-600kg/cm<2> pressure in a vacuum in the first stage, densified (so as to provide preferably >=95% theoretical density ratio) and simultaneously calcined. The resultant calcined compact is then hot- pressed at 1500-1700 deg.C under 100-600kg/cm<2> pressure in nitrogen gas or inert gas atmosphere in the second stage to provide a light-transmitting calcined spinel compact. The resultant light-transmitting calcined spinel compact exhibits the maximum >=75% linear transmittance at 3-5mum wavelength and 3mm simple thickness.