Sol-gel process for producing synthetic silica glass
OwnerRahul Ganguli, Enrico C.J. Westenberginventors
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Abstract
An improved sol-gel process is disclosed for producing a synthetic silica glass article, in which a sol is formed having a silica loading as high as 34 to 40%. This high loading is achieved by introducing an aqueous colloidal silica suspension into a silicon alkoxide solution and slowly stirring the mixture together, during which time the mixture hydrolyzes and the colloidal suspension is broken down by chemical reaction. This produces a hydrolyzed sol incorporating a suspension of very fine aggregates of colloidal particles, having particle sizes less than about 10 microns. The need for a stabilizing agent and/or continuous ultra-sonicating or violently stirring the sol is eliminated.
Claims17
A process for producing a synthetic silica glass article, comprising:
- combining an aqueous colloidal suspension with a silicon alkoxide solution to produce a mixture;
- allowing the mixture to hydrolyze into a sol containing fine aggregates of colloidal particles and then to gel into a wet gel;
- drying the wet gel to produce a dry gel;
- and
- sintering the dry gel to produce a dense silica glass article.
A process for producing a synthetic silica glass article, comprising:
- forming a mixture of silicon alkoxide, colloidal silica, and water, wherein the mixture is substantially free of a stabilizing agent and has a silica loading greater than about 30%, and wherein forming is performed without continuous ultra-sonicating or violently mixing the mixture;
- allowing the mixture to hydrolyze into a sol containing fine aggregates of silica particles and substantially free of agglomerated colloidal silica particles having a particle size greater than about 10 microns, and then allowing the sol to gel into a wet gel;
- drying the wet gel to produce a dry gel;
- and
- sintering the dry gel to produce a dense silica glass article.
Dependencies are inferred from the claim text.