Method of producing silicon carbide articles

Claim 1

A method of forming a shaped product having a surface layer of silicon carbide (SiC) reaction bonded to an inner structure consisting essentially of carbon, comprising the steps of: (a) generating SiO gas at a concentration of between about 5 and 50 volume percent by heating solid silicon dioxide (SiO 2 ) to a reaction temperature of between approximately 1500° and 1550° C. in an atmosphere of hydrogen, said solid silicon dioxide being in the form of a powder surrounding said structure: (b) contacting said structure with said SiO gas at said reaction temperature of between approximately 1500° C. and 1550° C. for a period of time sufficient to form a layer of SiC on the surface of said structure by chemical conversion of carbon in said structure to SiC, whereby a layer of reaction-bonded SiC is formed on the surface of said structure without significantly changing the dimensions of said structure.

Claim 2

A method of forming a shaped product having a surface layer of silicon carbide (SiC) reaction bonded to an inner structure consisting essentially of carbon, comprising the steps of: (a) generating SiO gas at a concentration of between about 5 and 50 volume percent by heating solid silicon dioxide (SiO 2 ) to a reaction temperature of between approximately 1500° and 1550° C. in an atmosphere of hydrogen, said solid silicon dioxide being in the form of a powder surrounding said structure: (b) contacting said structure with said SiO gas at said reaction temperature of between approximately 1500° C. and 1550° C. for a period of time sufficient to form a layer of SiC on the surface of said structure by chemical conversion of carbon in said structure to SiC, whereby a layer of reaction-bonded SiC is formed on the surface of said structure without significantly changing the dimensions of said structure.

Claim 5

A method of producing articles of manufacture which are reinforced with silicon carbide (SiC) whiskers, without destroying the integrity of the whiskers, comprising the steps of: (a) dispersing and mixing SiC whiskers in a mixture of solvent and resin with carbon or graphite particles of a size chosen from good mixing and efficient packing, so as to form resin bonded and coated fibers and particles; (b) allowing the solvent to evaporate from said mixture; (c) forming said resin bonded fibers and particles into a final shape in which said resin will finally be cured; (d) heating said final shape to about 800° C. to carbonize said resin and so as to form a carbon-bonded SiC whisker reinforced composite structure which is a non-abrasive matrix in which the whiskers maintain their structural integrity; (e) generating SiO gas at a concentration of at least 5 volume percent by heating solid silicon dioxide (SiO 2 ) to a reaction temperature of between approximately 1400° and 1600° C. in an atmosphere of hydrogen; and (f) contacting said SiC whisker reinforced composite structure with said SiO gas at said reaction temperature of between approximately 1400 C. and 1600° C. for a period of time sufficient to convert at least some of the carbon in said structure to SiC, whereby there is formed a structure containing SiC as well as SiC whiskers, and wherein said whiskers are not damaged by the fabrication process.

Claim 6

A method of producing articles of manufacture which are reinforced with silicon carbide (SiC) whiskers, without destroying the integrity of the whiskers, comprising the steps of: (a) dispersing and mixing SiC whiskers in a mixture of solvent and resin with carbon or graphite particles of a size chosen from good mixing and efficient packing, so as to form resin bonded and coated fibers and particles; (b) allowing the solvent to evaporate from said mixture; (c) forming said resin bonded fibers and particles into a final shape in which said resin will finally be cured; (d) heating said final shape to about 800° C. to carbonize said resin and so as to form a carbon-bonded SiC whisker reinforced composite structure which is a non-abrasive matrix in which the whiskers maintain their structural integrity; (e) generating SiO gas at a concentration of at least 5 volume percent by heating solid silicon dioxide (SiO 2 ) to a reaction temperature of between approximately 1400° and 1600° C. in an atmosphere of hydrogen; and (f) contacting said SiC whisker reinforced composite structure with said SiO gas at said reaction temperature of between approximately 1400 C. and 1600° C. for a period of time sufficient to convert at least some of the carbon in said structure to SiC, whereby there is formed a structure containing SiC as well as SiC whiskers, and wherein said whiskers are not damaged by the fabrication process.