Process for increasing strength of glass by forming ceramic coating on glass surface

Claim 1

A method for improving the rupture strength of a glass material by at least about 100% which comprises: a) forming a tractable organometallic polymeric preceramic liquid coating solution by dissolving in an organic solvent an organometallic polymeric preceramic coating material to provide a liquid preceramic coating solution: 1) capable of pyrolyzing to form a ceramic coating selected from the class consisting of silicides, borides, nitrides, carbides, and oxides at a temperature not exceeding the softening temperature of the glass material; 2) capable of providing a ceramic yield of at least 35 wt. %; 3) having a viscosity, after application to the glass material and removal of solvent, of at least 1 poise; and 4) capable of wetting and adhering to the glass material to form a uniform coating on the surface of the glass material; and b) coating an unannealed glass material with said preceramic liquid coating solution; c) heating said coated glass material in atmosphere selected from the group consisting of an inert atmosphere and a nitrogen-containing atmosphere, to a pyrolysis temperature of from about 300° C. to about 10° C. below the softening temperature of the glass to permit pyrolysis of the preceramic coating material without exceeding the softening temperature of said glass material; and d) maintaining said coated glass material at said pyrolysis temperature for a period of time sufficient to form the ceramic coating and remove those portions of said coating material which do not participate in forming said ceramic coating.

Claim 2

A method for improving the rupture strength of a glass material by at least about 100% which comprises: a) forming a tractable organometallic polymeric preceramic liquid coating solution by dissolving in an organic solvent an organometallic polymeric preceramic coating material to provide a liquid preceramic coating solution: 1) capable of pyrolyzing to form a ceramic coating selected from the class consisting of silicides, borides, nitrides, carbides, and oxides at a temperature not exceeding the softening temperature of the glass material; 2) capable of providing a ceramic yield of at least 35 wt. %; 3) having a viscosity, after application to the glass material and removal of solvent, of at least 1 poise; and 4) capable of wetting and adhering to the glass material to form a uniform coating on the surface of the glass material; and b) coating an unannealed glass material with said preceramic liquid coating solution; c) heating said coated glass material in atmosphere selected from the group consisting of an inert atmosphere and a nitrogen-containing atmosphere, to a pyrolysis temperature of from about 300° C. to about 10° C. below the softening temperature of the glass to permit pyrolysis of the preceramic coating material without exceeding the softening temperature of said glass material; and d) maintaining said coated glass material at said pyrolysis temperature for a period of time sufficient to form the ceramic coating and remove those portions of said coating material which do not participate in forming said ceramic coating.

Claim 19

A method for improving the rupture strength of a glass material by at least about 100% which comprises: a) forming a tractable silicon-based organometallic polymeric preceramic liquid coating solution by dissolving in an organic solvent a tractable preceramic coating material selected from the class consisting of polysilazane, polysiloxazane, and polysiloxane to form a liquid coating solution: 1) capable of pyrolyzing to form a ceramic coating at a temperature not exceeding the annealing temperature of the glass material; 2) having a sufficient molecular weight to provide a ceramic yield of at least 35 wt. %; 3) being a liquid having a minimum viscosity, after application to the glass material and removal of solvent, of at least 1 poise; and 4) capable of forming a uniform coating on the surface of the glass material; b) applying a coating of said silicon-based organometallic polymeric preceramic liquid coating solution on an unannealed glass material; c) heating said coated glass material in atmosphere selected from the group consisting of an inert atmosphere and a nitrogen-containing atmosphere to a pyrolysis temperature of from at least about 500° C. to about 10° C. below the softening temperature of the glass to permit pyrolysis of said preceramic coating material without exceeding the softening temperature of the glass; d) maintaining said coated glass material at said pyrolysis temperature for a period of time of at least about 45 minutes to form the ceramic coating and remove portions of the silicon-based organometallic polymer which do not form the ceramic coating; and e) cooling said coated glass material down to a temperature of about 200° C. at a rate not exceeding about 30° C. per minute.

Claim 20

A method for improving the rupture strength of a glass material by at least about 100% which comprises: a) forming a tractable silicon-based organometallic polymeric preceramic liquid coating solution by dissolving in an organic solvent a tractable preceramic coating material selected from the class consisting of polysilazane, polysiloxazane, and polysiloxane to form a liquid coating solution: 1) capable of pyrolyzing to form a ceramic coating at a temperature not exceeding the annealing temperature of the glass material; 2) having a sufficient molecular weight to provide a ceramic yield of at least 35 wt. %; 3) being a liquid having a minimum viscosity, after application to the glass material and removal of solvent, of at least 1 poise; and 4) capable of forming a uniform coating on the surface of the glass material; b) applying a coating of said silicon-based organometallic polymeric preceramic liquid coating solution on an unannealed glass material; c) heating said coated glass material in atmosphere selected from the group consisting of an inert atmosphere and a nitrogen-containing atmosphere to a pyrolysis temperature of from at least about 500° C. to about 10° C. below the softening temperature of the glass to permit pyrolysis of said preceramic coating material without exceeding the softening temperature of the glass; d) maintaining said coated glass material at said pyrolysis temperature for a period of time of at least about 45 minutes to form the ceramic coating and remove portions of the silicon-based organometallic polymer which do not form the ceramic coating; and e) cooling said coated glass material down to a temperature of about 200° C. at a rate not exceeding about 30° C. per minute.

Claim 21

A method for improving the rupture strength of a glass material by at least about 100% which comprises: a) forming a tractable silicon-based organometallic polymeric preceramic liquid coating solution by dissolving in an organic solvent of tetrahydrofuran a tractable preceramic coating material selected from the class consisting of polysilazane, polysiloxazane, and polysiloxane; b) applying a liquid coating of said silicon-based organometallic polymeric preceramic coating solution on an unannealed glass material; c) heating said coated glass material in atmosphere selected from the group consisting of an inert atmosphere and a nitrogen-containing atmosphere, to a pyrolysis temperature of from at least about 500° C. to about 10° C. below the softening temperature of the glass to permit pyrolysis of said preceramic coating material without exceeding the softening temperature of the glass; d) maintaining said coated glass material at said pyrolysis temperature for a period of time of at least about 45 minutes to form the ceramic coating and remove portions of the silicon-based organometallic polymer which do not form the ceramic coating; and e) cooling said coated glass material down to a temperature of about 200° C. at a rate not exceeding about 30° C. per minute.

Claim 22

A method for improving the rupture strength of a glass material by at least about 100% which comprises: a) forming a tractable silicon-based organometallic polymeric preceramic liquid coating solution by dissolving in an organic solvent of tetrahydrofuran a tractable preceramic coating material selected from the class consisting of polysilazane, polysiloxazane, and polysiloxane; b) applying a liquid coating of said silicon-based organometallic polymeric preceramic coating solution on an unannealed glass material; c) heating said coated glass material in atmosphere selected from the group consisting of an inert atmosphere and a nitrogen-containing atmosphere, to a pyrolysis temperature of from at least about 500° C. to about 10° C. below the softening temperature of the glass to permit pyrolysis of said preceramic coating material without exceeding the softening temperature of the glass; d) maintaining said coated glass material at said pyrolysis temperature for a period of time of at least about 45 minutes to form the ceramic coating and remove portions of the silicon-based organometallic polymer which do not form the ceramic coating; and e) cooling said coated glass material down to a temperature of about 200° C. at a rate not exceeding about 30° C. per minute.