An article may include a substrate, such as a silicon-containing ceramic matrix composite, an environmental barrier coating (EBC) layer on the substrate, and a CMAS-resistant EBC layer on the EBC layer. The EBC layer may include at least one rare-earth disilicate (REDS). The CMAS-resistant EBC layer may include at least one rare-earth monosilicate (REMS) configured to react with CMAS to form crystalline reaction products. The CMAS-resistant EBC layer may include a plurality of vertical cracks extending from a surface of the CMAS-resistant EBC layer at least partially into the CMAS-resistant EBC layer. Additionally, or alternatively, the EBC layer may include a plurality of vertical cracks extending from a surface of the EBC layer into at least a portion of the EBC layer.

A filter element for a particle filter having a porous filter body made of a ceramic material and including a plurality of flow channels extending fluidically in parallel. The filter body is provided at least in a part of the flow channels with a coating made of a coating material, which is different from the ceramic material and is made up of orthorhombic crystals. A particle filter, a method for producing a filter element, and the use of a coating material for coating a filter element is also provided.

A method for forming ceramic matrix composite (CMC) component includes forming a fiber preform, positioning the fiber preform into a chemical vapor infiltration reactor chamber, and densifying the fiber preform. Densification includes infiltrating the fiber preform with a first gas comprising precursors of silicon carbide and infiltrating the fiber preform with a second gas comprising a first rare earth element, wherein the steps of infiltrating the fiber preform with the first gas and infiltrating the fiber preform with the second gas are conducted simultaneously to produce a first rare earth-doped silicon carbide matrix in a first region of the component.

A method for forming ceramic matrix composite (CMC) component includes forming a fiber preform, positioning the fiber preform into a chemical vapor infiltration reactor chamber, and densifying the fiber preform. Densification includes infiltrating the fiber preform with a first gas comprising precursors of silicon carbide and infiltrating the fiber preform with a second gas comprising a first rare earth element, wherein the steps of infiltrating the fiber preform with the first gas and infiltrating the fiber preform with the second gas are conducted simultaneously to produce a first rare earth-doped silicon carbide matrix in a first region of the component.

A chamber component comprises a body and a plasma sprayed ceramic coating on the body. The plasma sprayed ceramic coating is applied using a method that includes feeding powder comprising a yttrium oxide containing solid solution into a plasma spraying system, wherein the powder comprises a majority of donut-shaped particles, each of the donut-shaped particles having a spherical body with indentations on opposite sides of the spherical body. The method further includes plasma spray coating the body to apply a ceramic coating onto the body, wherein the ceramic coating comprises the yttrium oxide containing solid solution, wherein the donut-shaped particles cause the ceramic coating to have an improved morphology and a decreased porosity as compared to powder particles of other shapes, wherein the improved surface morphology comprises a reduced amount of surface nodules.

A chamber component comprises a body and a plasma sprayed ceramic coating on the body. The plasma sprayed ceramic coating is applied using a method that includes feeding powder comprising a yttrium oxide containing solid solution into a plasma spraying system, wherein the powder comprises a majority of donut-shaped particles, each of the donut-shaped particles having a spherical body with indentations on opposite sides of the spherical body. The method further includes plasma spray coating the body to apply a ceramic coating onto the body, wherein the ceramic coating comprises the yttrium oxide containing solid solution, wherein the donut-shaped particles cause the ceramic coating to have an improved morphology and a decreased porosity as compared to powder particles of other shapes, wherein the improved surface morphology comprises a reduced amount of surface nodules.

There is provided a group III nitride laminate, including: a substrate comprised of silicon carbide; a first layer comprised of aluminum nitride and formed on the substrate; a second layer comprised of gallium nitride and formed on the first layer; and a third layer formed on the second layer and comprised of group III nitride having an electron affinity lower than that of the gallium nitride which is comprised in the second layer, the second layer having a thickness of less than 500 nm, the second layer containing iron at a concentration of less than 1×10.sup.17/cm.sup.3, and the second layer containing carbon at a concentration of less than 1×10.sup.17/cm.sup.3.

There is provided a group III nitride laminate, including: a substrate comprised of silicon carbide; a first layer comprised of aluminum nitride and formed on the substrate; a second layer comprised of gallium nitride and formed on the first layer; and a third layer formed on the second layer and comprised of group III nitride having an electron affinity lower than that of the gallium nitride which is comprised in the second layer, the second layer having a thickness of less than 500 nm, the second layer containing iron at a concentration of less than 1×10.sup.17/cm.sup.3, and the second layer containing carbon at a concentration of less than 1×10.sup.17/cm.sup.3.

The method includes forming an inner monolithic layer from crystals of beta phase stoichiometric silicon carbide on a carbon substrate in the form of a rod by chemical methylsilane vapor deposition in a sealed tubular hot-wall CVD reactor. The method further includes forming a central composite layer over the inner monolithic layer by twisting continuous beta phase stoichiometric silicon carbide fibers into tows, transporting the tows to a braiding machine, and forming a reinforcing thread framework. A pyrocarbon interface coating is built up by chemical methane vapor deposition in a sealed tubular hot-wall CVD reactor. Then, a matrix is formed by chemical methylsilane vapor deposition in the reactor. A protective outer monolithic layer is formed from crystals of beta phase stoichiometric silicon carbide over the central composite layer by chemical methylsilane vapor deposition in a CVD reactor. And then the carbon substrate is removed from the fabricated semi-finished product.

The method includes forming an inner monolithic layer from crystals of beta phase stoichiometric silicon carbide on a carbon substrate in the form of a rod by chemical methylsilane vapor deposition in a sealed tubular hot-wall CVD reactor. The method further includes forming a central composite layer over the inner monolithic layer by twisting continuous beta phase stoichiometric silicon carbide fibers into tows, transporting the tows to a braiding machine, and forming a reinforcing thread framework. A pyrocarbon interface coating is built up by chemical methane vapor deposition in a sealed tubular hot-wall CVD reactor. Then, a matrix is formed by chemical methylsilane vapor deposition in the reactor. A protective outer monolithic layer is formed from crystals of beta phase stoichiometric silicon carbide over the central composite layer by chemical methylsilane vapor deposition in a CVD reactor. And then the carbon substrate is removed from the fabricated semi-finished product.