Ceramic alloys from colloidal metal alloy suspensions
AssigneeHoechst Celanese Corporation
InventorRobert E. Johnson
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Abstract
Ceramic alloys or solid solutions are formed by dispersing a powdery metal alloy or intimate mixture of two alloying metals in a precarbonaceous polymer such as polyacrylonitrile, forming the mixture into a molded article such as fibers, and heating the molded articles at a temperature and in a pyrolyzation atmosphere sufficient to carbonize the polymer and cause reaction of the metals with carbon and/or the pyrolyzation gas.
Claims22
A process for preparing molded products of ceramic alloys which comprised molding a preceramic composition comprising (a) from about 5 to 95% by weight based on the composition of at least one powdery metal alloy or a unitary powdery intimate mixture of alloying metals or alloying metallic compounds, said powdery metal alloy or intimate mixture comprising at least one refractory metal or metal compound selected from silicon, boron and compounds of silicon or boron and a second alloying metal comprising aluminum which lowers the melting point of said alloy below the melting point of said refractory metal or metal compound and, wherein the average particle size of said powdery metal alloy or unitary powdery intimate mixture is not greater than about 50 microns, and (b) a precarbonaceous polymer, curing said molded preceramic composition to harden some and, heating said cured molded preceramic composition at a temperature and in a pyrolyzation atmosphere sufficient to carbonize said polymer and cause reaction between said powdery metal alloy or intimate mixture and carbon.
A process for preparing ceramic alloy fibers which comprises spinning into fiber a preceramic composition comprising (a) from about 5 to 95% by weight based on the composition of at least one powdery metal alloy or unitary powdery intimate mixture of alloying metals or alloying metallic compounds, said powdery metal alloy or intimate mixture comprising at least one refractory metal or metal compound selected from silicon, boron and compounds of silicon or boron and a second alloying metal comprising aluminum which lowers the melting point of said alloy below the melting point of said refractory metal or metal compound and wherein the average particle size of said powdery metal alloy or unitary powdery intimate mixture is not greater than about 50 microns, and (b) an acrylonitrile polymer, curing said preceramic fiber to harden same and, heating said cured fiber in a non-oxygen-containing atmosphere and at a temperature sufficient to carbonize said polymer and cause reaction between said powdery metal alloy or intimate mixture and carbon.
Dependencies are inferred from the claim text.