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 m; 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 m.

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 m; 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 m.

The present invention is directed to repair compositions for thermal barrier coatings and methods of use thereof. The repair compositions include a ceramic composition, a colloidal solution, an aqueous binder, an aqueous dispersant, and an aqueous ammonia solution. The ceramic composition includes a first population of yttria-stabilized zirconia particles having a mean diameter from about 250 nm to about 1000 nm, a second population of yttria-stabilized zirconia particles having a mean diameter from about 2 m to about 10 m, and a third population of yttria-stabilized zirconia particles having a mean diameter from about 20 m to about 250 m. One method includes depositing the repair layer onto the damaged region, the repair layer including the repair composition, and heat treating the repair layer.

The present invention is directed to repair compositions for thermal barrier coatings and methods of use thereof. The repair compositions include a ceramic composition, a colloidal solution, an aqueous binder, an aqueous dispersant, and an aqueous ammonia solution. The ceramic composition includes a first population of yttria-stabilized zirconia particles having a mean diameter from about 250 nm to about 1000 nm, a second population of yttria-stabilized zirconia particles having a mean diameter from about 2 m to about 10 m, and a third population of yttria-stabilized zirconia particles having a mean diameter from about 20 m to about 250 m. One method includes depositing the repair layer onto the damaged region, the repair layer including the repair composition, and heat treating the repair layer.

In some examples, a braze material includes a first set of particles, a second set of particles, and a polymeric binder. The first set of particles includes a braze powder, where the braze powder comprises an Si-containing alloy. The first set of particles defines an average or median particle diameter between about 1 m and about 40 m. The second set of particles includes at least one of SiC or a transition metal carbide, where the second set of particles has a multimodal particle size distribution.

In some examples, a braze material includes a first set of particles, a second set of particles, and a polymeric binder. The first set of particles includes a braze powder, where the braze powder comprises an Si-containing alloy. The first set of particles defines an average or median particle diameter between about 1 m and about 40 m. The second set of particles includes at least one of SiC or a transition metal carbide, where the second set of particles has a multimodal particle size distribution.

A circumferential coating material contains colloidal silica, silicon carbide, and titanium oxide different in particle diameters from silicon carbide, coats a circumferential surface of a honeycomb structure monolithically formed by extrusion, including as a main component, cordierite having a porosity of 50 to 75%, and forms a circumferential coating layer. A circumferentially coated honeycomb structure has a honeycomb structure comprising latticed porous partition walls defining and forming a plurality of polygonal cells forming through channels and extending from one end face to the other end face, and a circumferential coating layer formed by coating at least a part of a circumferential surface of the honeycomb structure with the circumferential coating material.

A circumferential coating material contains colloidal silica, silicon carbide, and titanium oxide different in particle diameters from silicon carbide, coats a circumferential surface of a honeycomb structure monolithically formed by extrusion, including as a main component, cordierite having a porosity of 50 to 75%, and forms a circumferential coating layer. A circumferentially coated honeycomb structure has a honeycomb structure comprising latticed porous partition walls defining and forming a plurality of polygonal cells forming through channels and extending from one end face to the other end face, and a circumferential coating layer formed by coating at least a part of a circumferential surface of the honeycomb structure with the circumferential coating material.

The invention provides dispersed inorganic mixed metal oxide pigment compositions in a non-aqueous media utilizing a dispersant having polyisobutylene succinic anhydride structure to disperse a mixed metal oxide pigment in the media. The metal oxide pigment is of the type used to colour ceramic or glass articles. A milling process using beads is also described to reduce the mixed metal oxide particle size to the desired range. A method of using the mixed metal oxide dispersion to digitally print an image on a ceramic or glass article using the dispersion jetted through a nozzle and subsequently firing the coloured article is also described.

The invention provides dispersed inorganic mixed metal oxide pigment compositions in a non-aqueous media utilizing a dispersant having polyisobutylene succinic anhydride structure to disperse a mixed metal oxide pigment in the media. The metal oxide pigment is of the type used to colour ceramic or glass articles. A milling process using beads is also described to reduce the mixed metal oxide particle size to the desired range. A method of using the mixed metal oxide dispersion to digitally print an image on a ceramic or glass article using the dispersion jetted through a nozzle and subsequently firing the coloured article is also described.