| 摘要 |
PURPOSE: Provided is a method for manufacturing transparent silica glass with good transparency and near theoretical density by vacuum sintering silica compacts derived from the silica sol, containing silica granules based on fumed silica and F- ions-contained salt. CONSTITUTION: The method for manufacturing transparent silica glass comprises the steps of: (i) preparing a slurry type silica sol(<=1micrometer) by dispersing granular silica powder in water, where the silica granules are obtained by adding silica powder, fumed silica(30-100nm), to distilled water, drying at 110deg.C, dry-milling, and calcining at 900-1100deg.C for 1-5hrs.; (ii) preparing a silica-dispersed solution by adding 0.01-2wt.%(based on silica-dispersed solution) of salts containing F- ions as gelation promoters to the silica slurry; (iii) pouring the silica sol into a mold and gelling; (iv) demolding to get a bulky gel; (v) drying at 40deg.C for 48hrs.; (vi) thermal treating at 5-50deg.C/hr to 300-600deg.C for removal of organics; (vii) thermal treating at 100deg.C/hr to 500-1000deg.C in Cl2 atmosphere for removal of hydroxide ions and metallic impurities; (viii) sintering at 1200-1700deg.C for 0.1-100hrs. under vacuum between 10-1 and 10-6torr. The step for removing foams in silica sol is optionally added to the next of step (ii). |
