Carbon composite article and method of making same

A method of making a composite article comprising the steps of:

• forming a starting substrate from a multiplicity of high temperature resistant fibers,
• exposing said starting substrate to an elevated temperature of between about 1000.degree. F. and about 1800.degree. F. for a period of time of between about 1 hour and about 100 hours,
• suspending said starting substrate within a first vacuum pressure controlled environment,
• forming an intermediate substrate by heating said starting substrate to a temperature of between approximately 1500.degree. F. and approximately 4200.degree. F. while exposing said starting substrate to a hydrocarbon gas to form a uniform layer of pyrolytic carbon about each of the fibers in said starting substrate,
• removing said intermediate substrate from said first controlled environment and forming it into a shaped substrate having the approximate shaped desired of the end product composite article,
• supporting said shaped substrate in a second controlled environment while heating said shaped substrate to a temperature of between approximately 1350.degree. F. and approximately 2500.degree. F.,
• forming a coated article by depositing about said fibers of said shaped substrate, through chemical vapor deposition, a silicon metal capable of reacting with carbon to form silicon carbide,
• removing said diffusion coated article from said second controlled environment,
• heating said article within a controlled environment to a temperature of between approximately 1350.degree. F. and approximately 2500.degree. F., and
• exposing said article to a gas containing carbon and silicon to form a uniform chemical vapor deposition coating of silicon carbide over the coated fibers, the fiber interstices, and the periphery of said diffusion coated article.

A method of making a composite article comprising the steps of:

• forming a starting substrate from a multiplicity of high temperature resistant fibers in the form of a woven material having a multiplicity of interwoven fibers said fibers being selected from a group consisting of ceramic matrial, pyrolyzed wool, rayon, polyacrylonitrile and pitch fibers,
• suspending said starting substrate within a first controlled environment,
• forming an intermediate substrate by heating said starting substrate to a temperature of between approximately 1500.degree. F. and approximately 4200.degree. F. while exposing said starting substrate to a hydrocarbon gas selected from a group consisting of methane, propane, ethane, butane, ethylene, acetylene and benzine to form a uniform layer of pyrolytic carbon about each of the fibers in said starting substrate,
• removing said intermediate substrate from said first controlled environment and forming it into a shaped substrate having the approximate shape desired of the end product composite article,
• supporting said shaped substrate in a second controlled environment at less than atmospheric pressure while heating said shaped substrate to a temperature of between approximately 1350.degree. F. and approximately 2500.degree. F.,
• forming a coated article by depositing about said fibers of said shaped substrate, through chemical vapor deposition, a metal capable of reacting with carbon, oxygen, boron and nitrogen, said metal being selected from a group consisting of silicon, boron, aluminum, magnesium, tantalum, hafnium, titanium, berillium, thorium and zirconium,
• removing said article from said second controlled environment and suspending it thereabove while maintaining said at a temperature of on the order of 3200.degree. F. for about fifteen minutes,
• removing said coated article from said second controlled environment,
• heating said article within a controlled environment to a temperature of between approximately 1350.degree. F. and approximately 2500.degree. F., and
• exposing said article to a halide gas containing carbon and silicon selected from a group consisting of dimethyldichlorosilane, silicon tetrachloride trichlorosilane, dichlorosilane silicon dichloride, silicon tetrabromide, tribromosilane, dibromosilane and silicon dibromide to form a uniform chemical vapor deposition coating of silicon carbide over the coated fibers and periphery of said diffusion coated article.

A method of making a composite article comprising the steps of:

• forming a starting substrate from a multiplicity of high temperature resistant fibers selected from a group consisting of ceramic, pyrolyzed wool, rayon, polyacrylonitrile and pitch fibers,
• exposing said starting substrate to an elevated temperature of about 1800.degree. F. for a period of time sufficient to thermally stabilize said substrate,
• suspending said starting substrate within a controlled environment,
• heating said shaped substrate to a temperature of between approximately 1350.degree. F. and approximately 2500.degree. F., and
• forming a coated article having a controlled degree of open porosity by depositing about said fibers of said starting substrate through chemical vapor deposition, a metal capable of reacting with carbon, oxygen, boron, silicon and nitrogen to form a carbide, oxide, boride, silicide and nitride.

A method of making a composite article comprising the steps of:

• forming a starting substrate from a granular material selected from a group consisting of silicon carbide and graphite,
• exposing said starting substrate to an elevated temperature of about 1600.degree.-2200.degree. F. for a period of time sufficient to thermally stabilize said substrate,
• suspending said starting substrate within a controlled environment,
• heating said shaped substrate to a temperature of between approximately 1350.degree. F. and approximately 2500.degree. F., and
• forming a coated article having a controlled degree of open porosity by depositing about said fibers of said starting substrate through chemical vapor deposition, a metal capable of reacting with carbon, oxygen, boron, silicon and nitrogen to form a carbide, oxide, boride, silicide and nitride.

A method of forming a refractory composite material, including the steps of:

• providing a plurality of discrete elements in the form of a substrate, the discrete elements having a first coefficient of thermal expansion,
• compressing the substrate formed from the discrete elements,
• heating the substrate, and
• passing gases through the heated substrate to apply to the substrate a matrix having a different coefficient of thermal expansion than that of the substrate and providing for a free movement of the matrix relative to the substrate, the matrix being formed from a first element having refractory properties and a second element chemically bound to the first element.