A method for the preparation of a composite article containing aerogel particles and ceramic fibers, as well as to a composite article obtained by this method, are described.

The present invention concerns a method for obtaining a finished or semi-finished zirconia-based article, the surface of the article having a metallic external appearance and non-zero surface electrical conductivity, wherein the method includes the steps of: taking at least one zirconia article, pre-shaped in its finished or semi-finished form; placing said article in a chamber in which a hydrogen and carbon/nitrogen gas mixture is heated; heating said article and the gas mixture using at least one resistive element traversed by an electric current to obtain dissociation of the hydrogen and carbon/nitrogen based gas molecules and an increase in the temperature of said article; keeping said article in the reactive atmosphere thus created to obtain diffusion of the carbon/nitrogen atoms in the external surface of said article.

A coating fabrication method includes providing engineered granules and thermally consolidating the engineered granules on a substrate to form a silicate-resistant barrier coating. Each of the engineered granules is an aggregate of at least one refractory matrix region and at least one calcium aluminosilicate additive region (CAS additive region) attached with the at least one refractory matrix region. In the thermal consolidation, the refractory matrix region from the engineered granules form grains of a refractory matrix of the silicate-resistant barrier coating and the CAS additive region from the engineered granules form CAS additives that are dispersed in grain boundaries between the grains.

A coating fabrication method includes providing engineered granules and thermally consolidating the engineered granules on a substrate to form a silicate-resistant barrier coating. Each of the engineered granules is an aggregate of at least one refractory matrix region and at least one calcium aluminosilicate additive region (CAS additive region) attached with the at least one refractory matrix region. In the thermal consolidation, the refractory matrix region from the engineered granules form grains of a refractory matrix of the silicate-resistant barrier coating and the CAS additive region from the engineered granules form CAS additives that are dispersed in grain boundaries between the grains.

In some examples, article used as a component for a turbine engine that operates in a high temperature environment. The article may include: a ceramic or ceramic matrix composite (CMC) substrate; and a coating on the ceramic or the CMC substrate, wherein the coating defines an outer surface of the article. The coating includes a plurality of surface features defining channels on the outer surface of the article. The channels are configured to modify a flow of molten Calcia-Magnesia-Alumina Silicate (CMAS) over the outer surface of the coating in a gas flow over the outer surface of the article to reduce accumulation of the molten CMAS on the outer surface of the article.

An article for high temperature service is presented herein. One embodiment is an article including a substrate having a silicon-bearing ceramic matrix composite; and a layer disposed over the substrate, wherein the layer includes silicon and a dopant, the dopant including aluminum. In another embodiment, the article includes a ceramic matrix composite substrate, wherein the composite includes a silicon-bearing ceramic and a dopant, the dopant including aluminum; a bond coat disposed over the substrate, where the bond coat includes elemental silicon, a silicon alloy, a silicide, or combinations including any of the aforementioned; and a coating disposed over the bond coat, the coating including a silicate (such as an aluminosilicate or rare earth silicate), yttria-stabilized zirconia, or a combination including any of the aforementioned.

An article includes a ceramic-based substrate and a barrier layer on the ceramic-based substrate. The barrier layer includes a matrix phase and gettering particles in the matrix phase. The gettering particles with an aspect ratio greater than one are aligned such that a maximum dimension of the gettering particles extends along an axis that is generally parallel to the substrate. The barrier layer includes a dispersion of diffusive particles in the matrix phase. A composite material and a method of applying a barrier layer to a substrate are also disclosed.

An article includes a ceramic-based substrate and a barrier layer on the ceramic-based substrate. The barrier layer includes a matrix phase and a network of gettering particles in the matrix phase. The gettering particles have an average maximum dimension between about 30 and 70 microns. The gettering particles have maximum dimensions that range from about 1 to 100 microns, and a dispersion of barium-magnesium alumino-silicate particles in the matrix phase. A composite material and a method of applying a barrier layer to a substrate are also disclosed.

Proposed are a part having a corrosion-resistant layer that minimizes peeling off and particle generation of a porous ceramic layer, a manufacturing process apparatus having the same, and a method of manufacturing the part.

An alumina-ceramic-based electrical insulator, to a method for producing the insulator, and to a vacuum tube includes the insulator. The electrical insulator is for insulating two electrodes of a vacuum tube through which a charged particle beam flows, the electrical insulator being formed of an alumina-based ceramic. The ceramic comprises a vitreous phase of between 2% and 8% by weight into which at least one metal oxide is diffused from a face of the electrical insulator.