Sol-gel method of manufacturing a silica glass article from silica with two particle sizes

摘要

A sol-gel method of producing a silica glass article using a silica composed of two different sizes of particles comprising a) forming a sol of the silica b) aging (at 15-50‹C) c) removing air bubbles and gelling and d) drying and heat treating the gel. The silica used is pyrogenic and has a particle size of from 5-100 nm (with a specific surface area of 50-400 m2g-1) and is mixed with heat treated agglomerated particles of size 2-15 Ám. The latter are formed by a) adding de-ionised water to the pyrogenic silica and mixing b) drying and selecting particles with a suitable diameter (10-850 Ám) and c) heat treating at a temperature of 500-1200‹C.