A method for forming a high temperature coating includes applying carbon powder to a surface of a carbon/carbon (C/C) composite substrate to force the carbon powder into one or more surface voids of the surface of the C/C composite substrate. The carbon powder has a substantially same composition and morphology as a surface portion of the C/C composite substrate. The method includes applying a metal slurry to the surface of the C/C composite substrate following the application of the carbon powder and reacting a metal of the metal slurry with carbon of the carbon powder and carbon of the surface portion of the C/C composite substrate to form a metal-rich antioxidant layer of a metal carbide on the C/C composite substrate.

A plasma processing device member according to the disclosure includes a base material and a film formed of a rare-earth element oxide, or a rare-earth element fluoride, or a rare-earth element oxyfluoride, or a rare-earth element nitride, the film being disposed on at least part of the base material. The film includes a surface to be exposed to plasma, the surface having an arithmetic mean roughness Ra of 0.01 μm or more and 0.1 μm or less, the surface being provided with a plurality of pores, and a value obtained by subtracting an average equivalent circle diameter of the pores from an average distance between centroids of adjacent pores is 28 μm or more and 48 μm or less. A plasma processing device according to the disclosure includes the plasma processing device member described above.

Methods of forming sintered coatings are provided, along with the resulting coatings on a substrate. The sintered coating may comprise a rare earth compound and a sintering aid, with the rare earth compound has the formula: A.sub.1−bB.sub.bZ.sub.1−dD.sub.dMO.sub.6 where A is Al, Ga, In, Sc, Y, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Fe, Cr, Co, Mn, Bi, or a mixture thereof; b is 0 to about 0.5; Z is Hf, Ti, or a mixture thereof; D is Zr, Ce, Ge, Si, or a mixture thereof; d is 0 to about 0.5; and M is Ta, Nb, or a mixture thereof. The coating may be densified at a sintering temperature, such as 1300° C. to 1600° C.

Methods for forming a coating on a surface of a substrate are provided. The method can include: preheating the surface of the substrate; spraying a slurry suspension onto the surface of the substrate to form a coating, wherein the slurry composition comprises a rare earth compound, a sintering agent, and a solvent, wherein the rare earth compound has the formula: A.sub.1-bB.sub.bZ.sub.1-dD.sub.dMO.sub.6 where A is Al, Ga, In, Sc, Y, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Fe, Cr, Co, Mn, Bi, or a mixture thereof; b is 0 to 0.5; Z is Hf, Ti, or a mixture thereof; D is Zr, Ce, Ge, Si, or a mixture thereof; d is 0 to 0.5; and M is Ta, Nb, or a mixture thereof; and thereafter, heat treating the coating to densify the coating from an initial porosity to a sintered porosity.

A dielectric composition includes dielectric particles, grain boundary phases, and segregations. The dielectric particles each include a perovskite compound represented by ABO.sub.3 as a main component. The grain boundary phases are located between the dielectric particles. The segregations exist in a part of the grain boundary phases and include at least Al, Si, and O. A molar ratio (Al/(Al+Si)) of an Al content to a total content of Al and Si in the segregations is 0.45 or more and 0.75 or less.

A doping method using an electric field includes stacking a sacrificial layer on a doped layer, disposing a doping material on the sacrificial layer, disposing electrodes on the doping material and the doped layer, respectively, and doping the doping material into the doped layer through oxidation, diffusion, and reduction of the doping material by the electric field.

A coating composition is described, for use in the foundry, in particular comprising particulate, amorphous silicon dioxide (SiO.sub.2) and an aqueous phase having a pH of at most 5, and also coated, waterglass-bound foundry molding elements, especially coated, waterglass-bound foundry molds and foundry cores, which each comprise a coating composition of the invention. Further described is the use of a coating composition of the invention for producing a coating on a waterglass-bound foundry molding element and a method for producing a waterglass-bound foundry molding element (mold or core) coated with a water-containing refractory coating. Likewise specified is a kit whose contents include a coating composition of the invention.

A decorative article (100) having an observed colour effect that is changeable depending on observer (200) viewing angle, the article comprising: a decorative element (110) comprising a front side (114) facing a forward direction and a back side (112) opposite the front side facing a rearward direction, wherein the back side comprises a back surface (113) having a first region (122) and a second region (124) surrounding the first region; a first coating (132) arranged on the first region of the back surface, the first coating causing a first colour effect (102); and a second coating (134) arranged on the second region of the back surface, the second coating causing a second colour effect (104) that differs from the first colour effect.

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 part includes a substrate having, adjacent to a surface of the substrate, at least a portion that is made of a material that contains silicon, and an environmental barrier formed on the surface of the substrate, the environmental barrier including a first layer including at least one first rare earth silicate and presenting grains with a mean size less than or equal to 1 μm; and a second layer covering the first layer, the second layer including at least one rare earth silicate and presenting grains with a mean size greater than 1 μm.