Fused silica and method of manufacture
AssigneeRaytheon Company
InventorsJohn Stanley Waugh, Joseph Matthew Wahl
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Abstract
A processing technique for production of fused silica for radomes and like elements is described. The processing technique includes forming a mixture of milled silica having an average particle size of about 1 to 5 microns, and a colloidal silica. This mixture is processed to form fused silica having substantially high strength.
Claims30
A method of forming a densified body of fused silica comprising the steps of:
- forming a mixture of a starting powder of silica having a maximum particle size of about 10 microns, and finely divided silica particles having an average and maximum particle size characteristic such that said finely divided particles remain substantially in suspension in said mixture;
- and
- forming said mixture into the densified body of silica.
A method of forming silica agglomerates comprising the steps of:
- forming a aqueous mixture of a starting powder of silica having an average particle size in the range of about 1 micron to 5 microns and a maximum particle size of about 10 microns, and of finely divided silica particles having an average and maximum particle size characteristic such that said finely divided particles remain substantially in suspension in said aqueous mixture;
- and
- providing from said mixture silica agglomerates of uniform shape comprising said starting powder of silica interspersed with said finely divided silica particles.
A method of providing a fused silica radome transparent to r.f. energy comprises the steps of:
- providing a starting powder of fused silica particles having an average particle size in the range of about 1 micron to 5 microns and a maximum particle size of about 10 microns;
- forming an aqueous mixture of said starting powder of fused silica and colloidal finely divided silica particles having a maximum particle size in the range of about 10 nanometers to 50 nanometers;
- removing water from said aqueous mixture to provide small agglomerates of silica starting powder and finely divided silica particles having a uniform shape;
- introducing said agglomerates of silica into a mold;
- subjecting said mold containing said silica agglomerates to an isostatic pressure to consolidate said agglomerates into a body;
- and
- sintering said body for a period of time over a temperature range to densify said body to obtain a final density of about 89 to 91% of theoretical density.
A method of forming fused silica comprising the steps of:
- providing an aqueous mixture of a starting powder of silica having an average particle size of about 1 micron to 5 microns and a maximum particle size of about 10 microns, and a finely particle suspension of silica;
- introducing said mixture into a mold comprised of a material which removes water from said aqueous mixture to allow said mixture to dry and provide a rigid body having substantially all of the water removed;
- and
- firing said rigid, dried body over a period of time and at a temperature to provide the body with a density in the range of about 89 to 91% of theoretical density.
A body comprised of at least about 98.5% vitreous silica having a substantially fine and uniform microstructure of fused particles having an average particle size of in the range about 1 micron to 5 microns and maximum particle size of about 10 microns.
A body comprising at least about 98.5% vitrified silica having a strength characteristic of at least about 8500 psi for said silica having a density of at least about 1.87 g/cm3.
Dependencies are inferred from the claim text.