BN Bonded BN fiber article and method of manufacture
AssigneeKennecott Corporation
InventorRobert S. Hamilton
Life of this patent
Estimating the term…
Abstract
A boron nitride bonded boron nitride fiber article and the method for its manufacture which comprises forming a shaped article with a composition comprising a bonding compound selected from boron oxide and boric acid and a structural fiber selected from the group consisting of boron oxide, boron nitride and partially nitrided boron oxide fibers, heating the composition in an anhydrous gas to a temperature above the melting point of the compound and nitriding the resulting article in ammonia gas.
Claims28
A method for manufacturing a boron nitride article comprising:
- (a) blending from about 0.5 to about 40 weight percent of a bonding compound selected from the group consisting of boron oxide, boric acid and mixtures thereof with from about 60 to about 99.5 weight percent of structural fiber manufactured from boron oxide, partially nitrided boron oxide, boron nitride or mixtures of such fibers in an anhydrous fluid vehicle in which the bonding compound and the structural fiber are insoluble, the bonding compound having a lower melting temperature than the melting or decomposition temperature of the structural fiber;
- (b) forming a shaped article with the resulting blend and removing sufficient fluid vehicle to permit intimate contact of the structural fiber with the bonding compound;
- (c) heating the shaped article in an anhydrous gas selected from the group consisting of inert gases, nitrogen, ammonia, carbon dioxide and mixtures thereof to a temperature above the melting temperature of the bonding compound and below the melting or decomposition temperature of the structural fiber for a time sufficient to melt at least some of the bonding compound to the structural fibers;
- and
- (d) heating the shaped article in an ammonia atmosphere to a sufficient temperature and for a sufficient time to convert the bonding compound and structural fibers to boron nitride.
An article having sufficient flexibility that samples 3 mm thick show no apparent cracking or deterioration when bent around a 1.5 cm diameter rod;
- said article comprising boron nitride fibers bonded together with from about 5 to 30 percent by weight of article of discrete boron nitride bonds, said discrete bonds between crossed fibers having an average maximum dimension of up to ten times the diameter of the boron nitride fiber and essentially all of said bonds having smooth non-porous surfaces.
An article having sufficient flexibility that samples 3 mm thick show no apparent cracking or deterioration when bent around a 1.5 cm diameter rod;
- said article comprising boron nitride fibers bonded together with from about 25 to about 70 percent by weight of article of boron nitride bonds, essentially all of said bonds having smooth non-porous surfaces.
Dependencies are inferred from the claim text.