TRANSPARENT ALUMINUM OXYNITRIDE SINTERED BODY AND PRODUCTION THEREOF

摘要

PURPOSE:To obtain a sintered body having superior linear transmissivity and optical uniformity in spite of its large size by making specified aluminum oxynitride powder dense by hot pressing under prescribed conditions in an atmosphere of gaseous nitrogen, etc., and by subjecting the dense powder to hot isostatic pressing (HIP). CONSTITUTION:Aluminum oxynitride powder having =99% purity and =3m2/g BET specific surface area is prepd. and made dense by hot pressing at 1,400-1,800 deg.C under 100-500kg/cm2 pressure in vacuum or in gaseous nitrogen. The dense powder having =95% theoretical density is subjected to HIP with an inert gas, gaseous nitrogen, gaseous oxygen or a mixture of such gases at 1,500-2,000 deg.C under =500kg/cm2 pressure.