| 摘要 |
PURPOSE:To easily reduce the content of impurities and crystal by heating and fusing a mixture of fluoride glass raw material powder introduced into a heating furnace while keeping the inside of the furnace in negative pressure with an inert gas introduced. CONSTITUTION:The mixture obtained by mixing the raw materials such as ZrF4, BaF2 by a desired ratio and adding NH4F.HF is introduced into a platinum crucible 1, which is covered with a cap 2, placed on a pan and introduced into a core pipe before closing a core pipe cap 10 to set. Next, the pressure in the furnace measured by a pressure gauge 8 is controlled to be -50-1000mm H2O by evacuating the furnace from a gas discharge opening 6 while introducing the inert gas such as dried gaseous Ar by the rate of 1-10l/min and automatically adjusting the gas flow rate operating an inlet valve 9 and an outlet valve 11. Next, the fluoride glass is produced by heating the inside of the furnace to a desired temp. by a heater 7 and fluorinating the oxides and hydroxides in the raw materials with HF produced by the decomposition of NH4.HF.
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