Coating systems on a surface of a CMC component, such as a CMC shroud, are provided. The coating system can include an environmental barrier coating on the surface of the CMC component and an abradable coating on the environmental barrier coating and defining an external surface opposite of the environmental barrier coating. The abradable coating includes a compound having the formula: Ln.sub.2ABO.sub.8, where Ln comprises scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, or mixtures thereof; A comprises Si, Ti, Ge, or a combination thereof; and B comprises Mo, W, or a combination thereof. In one embodiment, the abradable coating has a first coefficient of thermal expansion at an interface with the environmental barrier coating that changes to a second coefficient of thermal expansion at its external surface. Methods are also provided for applying an abradable coating onto a CMC component.

Coating systems on a surface of a CMC component, such as a CMC shroud, are provided. The coating system can include an environmental barrier coating on the surface of the CMC component and an abradable coating on the environmental barrier coating and defining an external surface opposite of the environmental barrier coating. The abradable coating includes a compound having the formula: Ln.sub.2ABO.sub.8, where Ln comprises scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, or mixtures thereof; A comprises Si, Ti, Ge, or a combination thereof; and B comprises Mo, W, or a combination thereof. In one embodiment, the abradable coating has a first coefficient of thermal expansion at an interface with the environmental barrier coating that changes to a second coefficient of thermal expansion at its external surface. Methods are also provided for applying an abradable coating onto a CMC component.

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.

Components having coating systems that include mud cracks, methods for forming the coating systems, and vehicles including the components are provided. The components include a substrate having silicon nitride and a coating system on a surface of the substrate. The coating system includes a first layer of a first coating material on the substrate, wherein the first coating material includes a rare earth silicate and has a first thickness measured in a direction perpendicular to the surface of the substrate, and a second layer of a second coating material on the first layer, wherein the second coating material includes a rare earth silicate and has a second thickness that is greater than the first thickness. The second layer includes mud cracks that extend from an exterior surface thereof toward the substrate, and the mud cracks have widths in a range of about 50 to 200 micrometers.

Components having coating systems that include mud cracks, methods for forming the coating systems, and vehicles including the components are provided. The components include a substrate having silicon nitride and a coating system on a surface of the substrate. The coating system includes a first layer of a first coating material on the substrate, wherein the first coating material includes a rare earth silicate and has a first thickness measured in a direction perpendicular to the surface of the substrate, and a second layer of a second coating material on the first layer, wherein the second coating material includes a rare earth silicate and has a second thickness that is greater than the first thickness. The second layer includes mud cracks that extend from an exterior surface thereof toward the substrate, and the mud cracks have widths in a range of about 50 to 200 micrometers.

Disclosed is a photocatalyst member including a glaze layer and a photocatalyst layer provided on the glaze layer, the photocatalyst layer is good in layer strength, water resistance, or abrasion resistance. More specifically, the photocatalyst member includes a base having a glaze layer and a photocatalyst layer that is provided on the glaze layer and contains titanium oxide and zirconium titanate, wherein the content of zirconium titanate in the photocatalyst layer is 15 to 75% by mass based on the total content of titanium oxide and zirconium titanate, and the content of zirconium titanate in an area from around an interface between the photocatalyst layer and the base to an median line in the thickness of the photocatalyst layer is larger than the content of zirconium titanate in an area near the external surface of the photocatalyst layer.

Disclosed is a photocatalyst member including a glaze layer and a photocatalyst layer provided on the glaze layer, the photocatalyst layer is good in layer strength, water resistance, or abrasion resistance. More specifically, the photocatalyst member includes a base having a glaze layer and a photocatalyst layer that is provided on the glaze layer and contains titanium oxide and zirconium titanate, wherein the content of zirconium titanate in the photocatalyst layer is 15 to 75% by mass based on the total content of titanium oxide and zirconium titanate, and the content of zirconium titanate in an area from around an interface between the photocatalyst layer and the base to an median line in the thickness of the photocatalyst layer is larger than the content of zirconium titanate in an area near the external surface of the photocatalyst layer.

A coated cutting tool includes a body and a hard and wear resistant PVD coating on the body, wherein the body is made from a cemented carbide, cermet, ceramics, polycrystalline diamond or polycrystalline cubic boron nitride based materials. Th coating includes a first (Ti,Al)-based nitride sub-coating and a second (Ti,Al)-based nitride sub-coating. The first (Ti,Al)-based nitride sub-coating can be a single layer, and the second (Ti,Al)-based nitride sub-coating can be a laminated structure, wherein the first (Ti,Al)-based nitride sub-coating includes a (Ti.sub.1-xAl.sub.x)N.sub.z-layer where 0.1<x<0.4, 0.6<z<1.2, and wherein the second (Ti,Al)-based nitride sub-coating includes a (Ti.sub.1-x1-y1Al.sub.x1Cr.sub.y1)N.sub.z1 layer where 0.5<x1<0.75, 0.05<y1<0.2, 0.6<z1<1.2.

A coated cutting tool includes a body and a hard and wear resistant PVD coating on the body, wherein the body is made from a cemented carbide, cermet, ceramics, polycrystalline diamond or polycrystalline cubic boron nitride based materials. Th coating includes a first (Ti,Al)-based nitride sub-coating and a second (Ti,Al)-based nitride sub-coating. The first (Ti,Al)-based nitride sub-coating can be a single layer, and the second (Ti,Al)-based nitride sub-coating can be a laminated structure, wherein the first (Ti,Al)-based nitride sub-coating includes a (Ti.sub.1-xAl.sub.x)N.sub.z-layer where 0.1<x<0.4, 0.6<z<1.2, and wherein the second (Ti,Al)-based nitride sub-coating includes a (Ti.sub.1-x1-y1Al.sub.x1Cr.sub.y1)N.sub.z1 layer where 0.5<x1<0.75, 0.05<y1<0.2, 0.6<z1<1.2.

A method of manufacturing a honeycomb structured body, includes providing an application jig. A sealing material paste is put on a peripheral surface of a pillar-shaped ceramic block. The application jig is set in such a manner that a first principal surface of the application jig faces upward and a second principal surface of the application jig faces downward. The ceramic block is placed inside a second opening section of the application jig. The ceramic block is passed through an opening section of the application jig so that a face defining the second opening section spreads an entire peripheral surface of the ceramic block with the sealing material paste to manufacture a honeycomb structured body with a peripheral sealing material layer formed on the peripheral surface of the ceramic block.