High temperature oxidation protection for composites

A method for forming an oxidation protection system on a densified composite structure, comprising:

• forming a boron-silicon-glass composite slurry comprising a boron compound forming between 20.0% and 25.0% of a weight percentage of the boron-silicon-glass composite slurry, a silicon compound forming between 27.0% and 32.0% of the weight percentage of the boron-silicon-glass composite slurry, a glass compound, and a carrier fluid, wherein the boron compound comprises boron compound particles having a first average particle size between 8.0 micrometer and 10 micrometers, and wherein the silicon compound includes a silicon compound particles having a second average particle size of between 500.0 nanometers and 1.5 micrometers;
• applying the boron-silicon-glass composite slurry to the densified composite structure;
• and
• heating the densified composite structure to a temperature sufficient to form a boron-silicon-glass layer on the densified composite structure.

A method for forming an oxidation protection system on a densified composite structure, comprising:

• forming a boron-silicon-glass composite slurry comprising a boron compound, a silicon compound, a glass compound, and a carrier fluid, wherein the boron compound comprises a first group of boron compound particles having a first average particle size and the silicon compound comprises a first group of silicon compound particles having a second average particle size, the second average particle size being less than the first average particle size, wherein the first average particle size of the first group of boron compound particles is about 9.3 micrometers, wherein the second average particle size of the first group of silicon compound particles is about 1 micrometer, wherein the boron compound further comprises a second group of boron compound particles having a third average particle size of about 0.7 micrometers, and wherein the boron-silicon-glass composite slurry comprises about 7.2% by weight boron carbide having the third average particle size of about 0.7 micrometers, about 16.9% by weight boron carbide having the first average particle size of about 9.3 micrometers, about 9.3% by weight silicon carbide having a fourth average particle size of about 17 micrometers, about 21.7% by weight silicon carbide having the second average particle size of about 1 micrometers, about 6.9% by weight borosilicate glass having a fifth average particle size of about 12.3 micrometers, and about 37.9% by weight carrier fluid;
• applying the boron-silicon-glass composite slurry to the densified composite structure;
• and
• heating the densified composite structure to a temperature sufficient to form a boron-silicon-glass layer on the densified composite structure, wherein the boron-silicon-glass layer forms an exterior surface of the oxidation protection system.