Silicon oxide based articles
AssigneeDegussa Novara Technology S.p.A.
InventorsGiulio Boara, Simone Pedretti, Andreas Rückemann, Massimo Sparpaglione
Life of this patent
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Abstract
Particularly shaped articles constituted by silicon oxide, as such or with suitable additives, prepared by room temperature molding according to a process comprising: preparation of a sol starting from a silicon alcoxide, or from a silicon alcoxide and at least a precursor of at least one of the additional elements; hydrolysis of the sol obtained thereby; addition of colloidal silica; pouring the resulting mixture into the desired mould; sol gelling and fast removal of the solid product; gel drying; gel densification by means of a thermal treatment at temperature ranging from 900 ° C to 1500 ° C. The articles can be used as preforms for the optic fiber spinning.
Claims21
1-4. (canceled)
A process for making a shaped article of silicon oxide, comprising:
- a) preparing a sol from a silicon alcoxide;
- b) allowing or inducing the hydrolysis of the sol prepared in step a);
- c) adding colloidal silica to the sol that has undergone hydrolysis according to step b) to form a sol mixture;
- d) pouring the sol mixture of step c) into a mould;
- e) allowing the sol mixture in said mould to form a gel and then removing it from said mould;
- f) drying the gel obtained in step e);
- and
- g) thermally treating the gel dried in step f) at a temperature of 900° C.-1500° C. to increase its density.
Dependencies are inferred from the claim text.