Method of forming glass or ceramic article
AssigneeCorning Glass Works
InventorGeorge W. Scherer
Life of this patent
Estimating the term…
Abstract
Suspensions of particulate oxides, e.g., fumed silica, are prepared in non-aqueous media and the suspensions are used to cast shapes for glass or ceramic products. The suspensions are formed and then caused to gel by means of an added gelling agent, and thereafter dried and, optionally, sintered to transparent glass or void-free ceramic products.
Claims37
A method for making a porous glass or ceramic product which comprises the steps of:
- (a) suspending a particulate glassy or crystalline oxide in a non-aqueous liquid vehicle to provide a stable fluid suspension of oxide particles, said particles having an average diameter not exceeding about 0.5 microns;
- (b) forming the suspension into a selected configuration corresponding to that of the product to be made and causing the suspension to gel in that configuration, gellation being caused by the addition to the suspension of a gelling agent in an amount at least effective to produce a gelled intermediate, and
- (c) drying the gelled intermediate while maintaining the configuration thereof to provide an integral, essentially crack-free porous product having the configuration of the gelled intermediate.
A method for making a non-porous glass or ceramic product which comprises:
- (a) suspending a particulate glassy or crystalline oxide in a non-aqueous liquid vehicle to provide a stable fluid suspension of oxide particles, said particles having an average diameter not exceeding about 0.5 microns;
- (b) forming the suspension into a selected configuration corresponding to that of the product to be made and causing the suspension to gel in that configuration, gellation being caused by the addition to the suspension of a gelling agent in an amount at least effective to produce a gelled intermediate;
- (c) drying the gelled intermediate while maintaining the configuration thereof to provide an integral, essentially crack-free porous product having the configuration of the gelled intermediate;
- and
- (d) consolidating the porous product by heating it to a temperature at least sufficient to sinter the porous product to a non-porous glass or ceramic product.
In the method for making a glass or ceramic product wherein a fluid composition comprising glass or ceramic precursors is gelled to provide a semisolid intermediate which is dried and, optionally, sintered to a non-porous product, the improvement wherein (a) the fluid composition is a non-aqueous suspension of a particulate glassy or crystalline oxide, the oxide having an average particle diameter not exceeding about 0.5 microns, (b) the suspension is destabilized by adding a gelling agent thereto, and (c) the suspension is formed, prior to gelation, into an intermediate having the configuration of the product.
In the method for making an optical waveguide fiber by first forming from a particulate glassy oxide material a porous glass preform comprising glass for the fiber core and/or cladding, thereafter heating the porous glass preform to consolidate the oxide particles to transparent non-porous glass, and thereafter further heating and drawing the transparent glass into optical fiber, the improvement wherein the porous glass preform is made by:
- (a) casting a stable fluid suspension of particulate glassy oxide material into a configuration for the preform, said suspension comprising one or more particulate glassy oxides in a non-aqueous vehicle, the oxides being composed of oxide particles not exceeding about 0.5 microns in diameter;
- (b) causing the cast suspension to gel in said configuration, by the addition of a gelling agent to the suspension, to provide a gelled casting;
- and
- (c) drying the gelled casting to remove the vehicle therefrom, thus to provide a substantially crack-free porous glass preform having the configuration of the gelled casting.
In the method for making an optical waveguide fiber by first forming from a particulate glassy oxide material a porous glass preform comprising glass for the fiber core and/or cladding, thereafter heating the porous glass preform to consolidate the oxide particles to transparent non-porous glass, and thereafter further heating and drawing the transparent glass into optical fiber, the improvement wherein the porous glass preform is made by:
- (a) preparing at least two stable fluid suspensions of particulate glassy oxide material, each suspension comprising one or more particulate glassy oxides in a non-aqueous vehicle, the oxide composition of each suspension differing from the oxide composition of the other suspensions but the oxide particles in all suspensions not exceeding about 0.5 microns in diameter;
- (b) casting the suspensions into a configuration for the preform while varying the relative proportions of the suspensions introduced into the casting to produce corresponding variations in the composition of the casting;
- (c) causing the cast suspensions to gel in the cast configuration, the addition of a gelling agent to the suspension, to provide a gelled casting;
- and
- (d) drying the gelled casting to remove the vehicle therefrom, thus to provide a crack-free porous glass preform having the configuration and composition variations of the gelled casting.
Dependencies are inferred from the claim text.