摘要:
Boron nitride is coated on filaments of elemental carbon and/or silicon carbide, the coated filaments are contacted with an infiltration-promoting material containing elemental carbon to produce a preform wherein the filaments are substantially parallel and each filament is enveloped with infiltration-promoting material, and the preform is infiltrated with molten silicon to produce a composite containing boron nitride coated filaments.
摘要:
Boron nitride is coated on filaments of elemental carbon and/or silicon carbide, the coated filaments are contacted with an infiltration-promoting material containing elemental carbon to produce a preform wherein the filaments are substantially parallel and each filament is enveloped with infiltration-promoting material, and the preform is infiltrated with a molten solution of boron and silicon producing a composite containing boron nitride coated filaments.
摘要:
Fibrous material is coated with boron nitride and a silicon-wettable material, the coated fibrous material is admixed with an infiltration-promoting material which is at least partly elemental carbon and the mixture is formed into a preform which is infiltrated with a molten solution of boron and silicon producing a composite containing boron nitride coated fibrous material.
摘要:
Fibrous material is coated with boron nitride and a silicon-wettable material, the coated fibrous material is admixed with an infiltration-promoting material which is at least partly elemental carbon and the mixture is formed into a preform which is infiltrated with a molten solution of boron and silicon producing a composite containing boron nitride coated fibrous material.
摘要:
Fibrous material is coated with boron nitride and a silicon-wettable material, the coated fibrous material is admixed with an infiltration-promoting material which is at least partly elemental carbon and the mixture is formed into a preform which is infiltrated with molten silicon producing a composite containing boron nitride coated fibrous material.
摘要:
A cationically-conductive sodium beta"-alumina electrolyte showing asymmetric polarization is contacted with phosphoric acid to produce an etched electrolyte showing no asymmetric polarization.
摘要:
An alkali metal beta- and/or beta"-alumina polycrystalline body is chemically polished by contacting it at a polishing temperature with phosphoric acid of polishing concentration.
摘要:
A composite is comprised of reinforcement fibers having a continuous coating with a first layer of a metal oxide wherein the metal is from the group consisting of aluminum, yttrium, titanium, zirconium, beryllium, silicon, and the rare earths, and a molten silicon infiltration formed silicon carbide matrix. The coating may have a second layer from the group consisting of rhodium, iridium, metal carbide, metal silicide, metal nitride, and metal diboride, on the metal oxide coating. The reinforcement fibers being fibers from the group consisting of elemental carbon, silicon carbide, and mixtures thereof. A process for producing the fiber reinforced composite comprises depositing on the fibers a continuous coating comprised of the first layer of the metal oxide, and the second layer. A carbonaceous material is admixed with the coated fibers so that at least 5 volume percent of the mixture is the fibers. The mixture is formed into a preform having an open porosity ranging from about 25 volume percent to about 90 volume percent of the preform. The preform is heated in an inert atmosphere or partial vacuum, and infiltrated with molten silicon to produce an infiltrated product having the composition of the composite.
摘要:
A composite is produced by forming tapes comprised of a mixture of infiltration-promoting material and organic binding material, disposing a layer of boron nitride coated fibrous material between at least two of the tapes forming a layered structure, laminating the layered structure, heating the layered structure to remove organic binding material and infiltrating the resulting porous body with molten silicon.
摘要:
A composite is produced by admixing a matrix-forming material with organic binding material, forming the resulting mixture into a tape, disposing a layer of spaced boron nitride coated filaments between at least two of the tapes to form a layered structure, laminating the layered structure, heating the layered structure to remove organic binding material and hot pressing the resulting porous structure to form a composite containing spaced boron nitride coated filaments.