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.

A roller for a roller furnace with a roller base body and a coating on the surface, wherein the coating has a first layer, containing: 10.0-30.0 wt.-% Si, 10.0-30.0 wt.-% Al(OH).sub.3, 1.0-3.0 wt.-% B.sub.4C, 0.5-1.5 wt.-% Y.sub.2O.sub.3, 0.1-1.0 wt.-% Fe.sub.2O.sub.3 and the remainder Al.sub.2O.sub.3 and a second layer, containing 10.0-30.0 wt.-% Si, 10.0-30.0 wt.-% Al(OH).sub.3, 1.0-3.0 wt.-% B.sub.4C, 2.0-4.0 wt.-% Y.sub.2O.sub.3 and the remainder Al.sub.2O.sub.3.

A roller for a roller furnace with a roller base body and a coating on the surface, wherein the coating has a first layer, containing: 10.0-30.0 wt.-% Si, 10.0-30.0 wt.-% Al(OH).sub.3, 1.0-3.0 wt.-% B.sub.4C, 0.5-1.5 wt.-% Y.sub.2O.sub.3, 0.1-1.0 wt.-% Fe.sub.2O.sub.3 and the remainder Al.sub.2O.sub.3 and a second layer, containing 10.0-30.0 wt.-% Si, 10.0-30.0 wt.-% Al(OH).sub.3, 1.0-3.0 wt.-% B.sub.4C, 2.0-4.0 wt.-% Y.sub.2O.sub.3 and the remainder Al.sub.2O.sub.3.

A coating for an article includes a seal coat comprising self-healing particles disposed in a seal coat matrix and a bond coat disposed on the seal coat. The bond coat includes a matrix, diffusive particles disposed in the matrix, and gettering particles disposed in the matrix. A coating for an article and a method of applying a coating to an article are also disclosed.

A coating for an article includes a seal coat comprising self-healing particles disposed in a seal coat matrix and a bond coat disposed on the seal coat. The bond coat includes a matrix, diffusive particles disposed in the matrix, and gettering particles disposed in the matrix. A coating for an article and a method of applying a coating to an article are also disclosed.

A method for coating a ceramic matrix composite part with an environmental barrier, includes a) applying, to the surface of the part, a coating composition including a first powder of a rare earth silicate and a second powder including boron, the coating composition having a ratio R=[mass of the second powder]/[mass of the first powder] of between 0.1% and 5%, wherein the second powder includes a boron powder, and b) sintering the first and second powders in order to obtain the environmental barrier on the part.

A method for coating a ceramic matrix composite part with an environmental barrier, includes a) applying, to the surface of the part, a coating composition including a first powder of a rare earth silicate and a second powder including boron, the coating composition having a ratio R=[mass of the second powder]/[mass of the first powder] of between 0.1% and 5%, wherein the second powder includes a boron powder, and b) sintering the first and second powders in order to obtain the environmental barrier on the part.

Methods for repairing composite component voids are provided. For example, one method comprises locating a void in a composite component and subjecting the composite component to a process for repair. The process for repair includes creating a flow path through the void, applying a filler material to the composite component at the flow path, and processing the composite component having the filler material. In some embodiments, the flow path has a first opening on a first side of the composite component and a second opening on a second, opposite side of the composite component. In other embodiments, at least one portion of the flow path extends at a first angle with respect to a lateral direction defined by the CMC component, and at least another portion extends at a second angle with respect to the lateral direction.

Methods for repairing composite component voids are provided. For example, one method comprises locating a void in a composite component and subjecting the composite component to a process for repair. The process for repair includes creating a flow path through the void, applying a filler material to the composite component at the flow path, and processing the composite component having the filler material. In some embodiments, the flow path has a first opening on a first side of the composite component and a second opening on a second, opposite side of the composite component. In other embodiments, at least one portion of the flow path extends at a first angle with respect to a lateral direction defined by the CMC component, and at least another portion extends at a second angle with respect to the lateral direction.

A method of protecting a carbon-containing composite material part against oxidation, includes applying a first coating composition in the form of an aqueous suspension on an outside surface of the part, the first coating composition including a metallic phosphate; a powder of an ingredient comprising titanium; and a powder of B.sub.4C; subjecting the applied first coating composition to heat treatment in order to obtain a first coating on the outside surface of the part; applying a second coating composition on the first coating composition, the second coating composition including an aqueous suspension of colloidal silica; a powder of borosilicate glass; and a powder of TiB.sub.2; and subjecting the applied second coating composition to second heat treatment in order to obtain a second coating on the first coating.