A sintered body includes a ceramic substrate including sintered oxide particles, a through-hole formed in the ceramic substrate such that the side surfaces of the oxide particles exposed from an inner wall of the through-hole form a flat surface, and a porous body disposed in the through-hole, the porous body including spherical oxide ceramic particles and a mixed oxide configured to bind the spherical oxide ceramic particles.

In one example, a method for forming a coating system including a bond coat and an environmental barrier coating on a ceramic or CMC substrate, e.g., with an abradable coating on the environmental barrier coating. The method may include depositing a bond coat on a ceramic or ceramic matrix composite (CMC) substrate to form an as-deposited bond coat; heat treating the as-deposited bond coat following the deposition of the as-deposited bond coat on the substrate to form a heat treated bond coat; depositing an environment barrier coating (EBC) layer on the heat treated bond coat to form as deposited EBC layer; and heat treating the as-deposited EBC layer to form a heat treated EBC layer.

In one example, a method for forming a coating system including a bond coat and an environmental barrier coating on a ceramic or CMC substrate, e.g., with an abradable coating on the environmental barrier coating. The method may include depositing a bond coat on a ceramic or ceramic matrix composite (CMC) substrate to form an as-deposited bond coat; heat treating the as-deposited bond coat following the deposition of the as-deposited bond coat on the substrate to form a heat treated bond coat; depositing an environment barrier coating (EBC) layer on the heat treated bond coat to form as deposited EBC layer; and heat treating the as-deposited EBC layer to form a heat treated EBC layer.

Disclosed is a ceramic honeycomb structure comprising a honeycomb body and a multilayered outer layer formed of a thick core layer applied and rapidly dried and a thin clad layer dried more gently to form a crack free dual skin layer. The core layer may have properties that are closer to those of the ceramic honeycomb body in service than the clad layer that may provide a tough outer shell to withstand handling and assembly.

Disclosed is a ceramic honeycomb structure comprising a honeycomb body and a multilayered outer layer formed of a thick core layer applied and rapidly dried and a thin clad layer dried more gently to form a crack free dual skin layer. The core layer may have properties that are closer to those of the ceramic honeycomb body in service than the clad layer that may provide a tough outer shell to withstand handling and assembly.

A method for coating a substrate includes spraying a combination of powders. The combination of powders includes: Hf.sub.0.5Si.sub.0.5O.sub.2; Zr.sub.0.5Si.sub.0.5O.sub.2; and, optionally, at least one of HfO.sub.2 and ZrO.sub.2. A molar ratio of said Hf.sub.0.5Si.sub.0.5O.sub.2 and HfO.sub.2 combined to said Zr.sub.0.5Si.sub.0.5O.sub.2 and ZrO.sub.2 combined is from 2:1 to 4:1. A molar ratio of said Hf.sub.0.5Si.sub.0.5O.sub.2 to said HfO.sub.2 is at least 1:3.

A method for coating a substrate includes spraying a combination of powders. The combination of powders includes: Hf.sub.0.5Si.sub.0.5O.sub.2; Zr.sub.0.5Si.sub.0.5O.sub.2; and, optionally, at least one of HfO.sub.2 and ZrO.sub.2. A molar ratio of said Hf.sub.0.5Si.sub.0.5O.sub.2 and HfO.sub.2 combined to said Zr.sub.0.5Si.sub.0.5O.sub.2 and ZrO.sub.2 combined is from 2:1 to 4:1. A molar ratio of said Hf.sub.0.5Si.sub.0.5O.sub.2 to said HfO.sub.2 is at least 1:3.

A method includes feeding at least one ceramic feedstock into a heating zone of a thermal spray apparatus to form a heated ceramic feedstock. The heated ceramic feedstock is entrained in a plasma gas to form a heated gas stream directed toward a target surface of a CMC substrate. A sacrificial composition is fed with a sacrificial composition feed apparatus into the heated gas stream downstream of the heating zone at a selected injection angle α of about −30° to about +30° with respect to a plane of the target surface of the substrate. The heated ceramic feedstock is deposited from the heated gas stream onto the target surface to form a coating thereon. The thermal spray apparatus and the sacrificial composition feed system are configured to independently control a chemistry and a porosity of the coating.

A method includes feeding at least one ceramic feedstock into a heating zone of a thermal spray apparatus to form a heated ceramic feedstock. The heated ceramic feedstock is entrained in a plasma gas to form a heated gas stream directed toward a target surface of a CMC substrate. A sacrificial composition is fed with a sacrificial composition feed apparatus into the heated gas stream downstream of the heating zone at a selected injection angle α of about −30° to about +30° with respect to a plane of the target surface of the substrate. The heated ceramic feedstock is deposited from the heated gas stream onto the target surface to form a coating thereon. The thermal spray apparatus and the sacrificial composition feed system are configured to independently control a chemistry and a porosity of the coating.

Methods of forming an environmental barrier coating are disclosed. A method includes disposing a powder-based coating on a substrate, heat-treating the powder-based coating at a temperature greater than 800° C. and less than 1200° C. to form a porous coating that includes surface-connected pores, infiltrating at least some of the surface-connected pores of the porous coating with an infiltrant material to form an infiltrated coating, and sintering the infiltrated coating at a temperature greater than 1200° C. and less than 1500° C. to form the environmental barrier coating on the substrate.