| 摘要 |
PURPOSE:To provide a method for forming a porous glass material in improved yield of acceptable product using a pressure forming means. CONSTITUTION:Quartz glass powder 63 filled in a forming space 20 is compressed from outside of the forming mold to form a porous glass material 64 on the outer circumference of a rod 61 set in the forming space 20. In the above process, the quartz glass powder contains >=50% of granulated powder having particle diameter of >=30mum and <10% of fine powder having particle diameter of <=10mum. A porous glass material 64 having high quality and free from crack, craze, deviation of bulk density, dimensional error, etc., and giving a transparent glass free from residual bubbles can be produced in high yield by this process. |
