Glass fiber reinforced ceramic preform and method of casting it
AssigneeThe Boeing Company
InventorsAnna L. Bendig, Bruce L. Zornes
Life of this patent
Estimating the term…
Abstract
Freestanding glass reinforced ceramic protective coatings are made with a shrinkable silica preform technique. The coatings may be bonded to heat sensitive organic (plastic) or inorganic (ceramic or metal) substrates to provide thermal and impact protection.
Claims21
A method for forming a freestanding, net-shaped, glass fiber reinforced ceramic protective coating useful for providing thermal and/or impact protection to heat senstitive materials, which cannot withstand the normal firing of glass coating, comprising the steps of:
- (a) laying an aluminoborosilicate glass fiber cloth on a silica fiber preform of predetermined shape;
- (b) applying a slurry of glass powder to the cloth;
- (c) drying the slurry;
- (d) firing the perform, slurry, and cloth to melt the glass powder so that the glass forms a smooth surface on the cloth and to shrink the silica preform away from the cloth to release the cloth and glass from the preform without need of other release agents;
- and
- (e) cooling the glass and cloth to form the freestanding ceramic coating that is separable from the preform.
A composite, comprising:
- (a) a heat sensitive substrate which is unable to withstand the firing temperature necessary to form a protective glass coating directly on the substrate;
- and
- (b) a freestanding glass fiber reinforced protective glass coating made in a process not involving the substrate, bonded to one surface of the substrate;
- wherein the glass coating comprises borosilicate glass reinforced with a boron nitride barrier coated aluminoborosilicate fiber cloth.
A method for making a composite having a protective glass coating on at least one surface of a heat sensitive substrate which cannot withstand the direct firing of the glass to form the coating directly on the substrate, comprising the steps of:
- (a) forming a substrate into a predetermined shape, the substrate being heat sensitive so that the substrate cannot be fired at the melting temperature of glass powders;
- (b) forming a preform from silica fibers, the perform having a substantially identical shape with the substrate;
- (c) laying up ceramic glass fiber cloth on at least one surface of the perform;
- (d) applying a slurry of the glass powders to the cloth on the perform;
- (e) drying the slurry;
- (f) firing the perform, slurry, and cloth at a temperature higher than that temperature which the substrate can withstand to melt the glass powder so that the glass forms a smooth surface on the cloth and to shrink the perform away from the cloth to release the glass and cloth as a unitary coating free from the perform;
- (g) cooling the glass and cloth to produce a freestanding glass protective coating that is separable from the preform;
- and
- (h) bonding the freestanding glass protective coating to the corresponding surface of the substrate to form the composite.
A method for forming a freestanding, net-shaped, ceramic glass fiber reinforced ceramic protective coating useful for providing thermal and/or impact protection to heat sensitive materials, which cannot withstand the normal firing of glass coating, comprising the steps of:
- (a) laying up a ceramic glass fiber cloth on a silica fiber preform of predetermined shape;
- (b) applying a slurry of glass powder to the cloth;
- (c) firing the preform, cloth and slurry to at least about 2000.degree. F. for at least about 2-5 min to melt the glass powder and to shrink the preform away from the cloth;
- and
- (d) cooling the glass and cloth to solidify the glass and to form a freestanding ceramic coating separable from the silica preform.
A method for forming a freestanding, net-shaped glass fiber reinforced ceramic protective coating useful for providing thermal and/or impact protection to heat sensitive materials, which cannot withstand the normal firing of glass coating, comprising the steps of:
- (a) laying a ceramic fiber cloth on a silica fiber preform of predetermined shape;
- (b) applying a slurry of glass powder to the cloth;
- (c) drying the slurry;
- (d) firing the perform, slurry, and cloth to at least about 2000.degree. F. to melt the glass powder so that the glass forms a smooth surface on the cloth and to shrink the silica preform away from the cloth to release the cloth and glass from the preform without need of other release agents;
- (e) cooling the glass and cloth to solidify the glass and to form the ceramic coating;
- and
- (f) separating the ceramic coating from the silica preform.
A method for making a composite having a ceramic protective coating on at least one surface of a substrate, comprising the steps of:
- (a) forming a reinforced, ceramic coating by firing a slurry of glass powder coated onto a boron nitride barrier coated aluminoborosilicate fiber cloth;
- and
- (b) bonding the coating of step (a) to the surface of the substrate.
Dependencies are inferred from the claim text.