A method of forming a B.sub.4C layer as a component of an oxidation protection system as component of oxidation protection system on a carbon-carbon composite material may include forming a liquid mixture comprising a boron-compound and a carbon-compound. The method may further include applying the liquid mixture on the carbon-carbon composite material. The boron compound may comprise boric acid (H.sub.3BO.sub.3). In various embodiments, the carbon-compound comprises phenolic resin. In various embodiments, the method further includes heating the carbon-carbon composite material after applying the liquid mixture on the carbon-carbon composite material to from a boron carbide (B.sub.4C) layer.

A method of forming a B.sub.4C layer as a component of an oxidation protection system as component of oxidation protection system on a carbon-carbon composite material may include forming a liquid mixture comprising a boron-compound and a carbon-compound. The method may further include applying the liquid mixture on the carbon-carbon composite material. The boron compound may comprise boric acid (H.sub.3BO.sub.3). In various embodiments, the carbon-compound comprises phenolic resin. In various embodiments, the method further includes heating the carbon-carbon composite material after applying the liquid mixture on the carbon-carbon composite material to from a boron carbide (B.sub.4C) layer.

A method for coating a composite structure, comprising applying a first slurry onto a surface of the composite structure, wherein the first slurry is a sol gel comprising a metal organic salt, a first carrier fluid, and a ceramic material, and heating the composite structure to a first sol gel temperature sufficient to form a sol gel-derived base layer on the composite structure.

A method for coating a composite structure, comprising applying a first slurry onto a surface of the composite structure, wherein the first slurry is a sol gel comprising a metal organic salt, a first carrier fluid, and a ceramic material, and heating the composite structure to a first sol gel temperature sufficient to form a sol gel-derived base layer on the composite structure.

A method for coating a composite structure, comprising applying a first slurry onto a surface of the composite structure, wherein the first slurry is a sol gel comprising a metal organic salt, a first carrier fluid, and a ceramic material, and heating the composite structure to a first sol gel temperature sufficient to form a sol gel-derived base layer on the composite structure.

A method for coating a composite structure, comprising applying a first slurry onto a surface of the composite structure, wherein the first slurry is a sol gel comprising a metal organic salt, a first carrier fluid, and a ceramic material, and heating the composite structure to a first sol gel temperature sufficient to form a sol gel-derived base layer on the composite structure.

A method for producing a coating system includes depositing a first slurry on a composite substrate, the first slurry including a first carrier fluid and boron-containing powder, removing the first carrier fluid and consolidating the boron-containing powder to form a boron-containing layer on the composite substrate, depositing a silicon-containing coating on the boron-containing layer and consolidating the silicon-containing coating to form a silicon-containing layer, and depositing at least one layer of phosphate on the silicon-containing layer.

A method for producing a coating system includes depositing a first slurry on a composite substrate, the first slurry including a first carrier fluid and boron-containing powder, removing the first carrier fluid and consolidating the boron-containing powder to form a boron-containing layer on the composite substrate, depositing a silicon-containing coating on the boron-containing layer and consolidating the silicon-containing coating to form a silicon-containing layer, and depositing at least one layer of phosphate on the silicon-containing layer.

Systems and methods for forming an oxidation protection system on a composite structure are provided. In various embodiments, an oxidation protection system disposed on a substrate may comprise a boron-silicon-glass layer formed directly on the composite structure. The boron-silicon-glass layer may comprise a boron compound, a silicon compound, and a glass compound.

An oxidation protection system disposed on a substrate is provided, which may comprise a boron layer comprising a boron compound disposed on the substrate; a silicon layer comprising a silicon compound disposed on the boron layer; and at least one sealing layer comprising monoaluminum phosphate and phosphoric acid disposed on the silicon layer.