Ceramic materials from polycarbosilanes

Claim 1

A method of preparing a ceramic material with increased ceramic yield, said method comprising heating a modified polycarbosilane in an inert atmosphere or in a vacuum to a temperature of at least 750° C. until said modified polycarbosilane is converted to a ceramic material with increased ceramic yield relative to a non-modified polycarbosilane heated under the same conditions, wherein said modified polycarbosilane is prepared by mixing the non-modified polycarbosilane with an effective, ceramic yield increasing, amount of iron octoate, wherein the non-modified polycarbosilane is prepared by thermally decomposing and polycondensing a polysilane or polysilanes by heating said polysilane or polysilanes at a temperature of 300°-2000° C. in an inert gas, hydrogen, or vacuum wherein said polysilane or polysilanes are selected from the group consisting of cyclic polysilanes of the general formula (R.sup.1 R.sup.2 Si).sub.n and linear polysilanes of the general formula ##STR2## where n is greater than or equal to 4; where m is greater than or equal to 2; and where R 1 , R 2 , R 3 , and R 4 are independently selected from the group consisting of hydrogen, alkyl groups containing 1 to 4 carbon atoms, phenyl, --Si(R 5 ) 3 groups where R 5 is an alkyl group containing 1 to 4 carbon atoms, and halogen atoms.

Claim 2

A method of preparing a ceramic material with increased ceramic yield, said method comprising heating a modified polycarbosilane in an inert atmosphere or in a vacuum to a temperature of at least 750° C. until said modified polycarbosilane is converted to a ceramic material with increased ceramic yield relative to a non-modified polycarbosilane heated under the same conditions, wherein said modified polycarbosilane is prepared by mixing the non-modified polycarbosilane with an effective, ceramic yield increasing, amount of iron octoate, wherein the non-modified polycarbosilane is prepared by thermally decomposing and polycondensing a polysilane or polysilanes by heating said polysilane or polysilanes at a temperature of 300°-2000° C. in an inert gas, hydrogen, or vacuum wherein said polysilane or polysilanes are selected from the group consisting of cyclic polysilanes of the general formula (R.sup.1 R.sup.2 Si).sub.n and linear polysilanes of the general formula ##STR2## where n is greater than or equal to 4; where m is greater than or equal to 2; and where R 1 , R 2 , R 3 , and R 4 are independently selected from the group consisting of hydrogen, alkyl groups containing 1 to 4 carbon atoms, phenyl, --Si(R 5 ) 3 groups where R 5 is an alkyl group containing 1 to 4 carbon atoms, and halogen atoms.