| 摘要 |
PURPOSE:To improve light transmittance by putting powder or granule of high- purity Al2O3 into a W crucible, maintain in specific degree of vacuum at specific temperature, melting and coagulating in the crucible. CONSTITUTION:Powder or granular of high-purity Al2O3 is put into a high-purity W crucible and changed in a vacuum furnace. Then the furnace is evacuated to 10<-5> to 10<-15>Torr degree of vacuum, heated to >=2,054 deg.C, Al2O3 is melted, maintained for a given time, then cooled to room temperature and molten Al2O3 is coagulated. A nonoxidizing gas such as Ar is charged into the furnace, returned to normal pressure, the crucible is taken out to give light-transmitting Al2O3. |
