Abstract: A seal system a ceramic component having a surface region defining a first surface roughness, a metallic component situated adjacent the surface region, and a coating system disposed on the surface region. The coating system includes a silicon-containing layer on the surface region and a barrier layer on the silicon-containing layer. The silicon-containing layer has a surface in contact with the barrier layer. The barrier layer has a surface in contact with the metallic component. The surface of the barrier layer has a second surface roughness that is less than the first surface roughness. The barrier layer limits interaction between silicon of the silicon-containing layer and elements of the metallic component. The barrier layer has a coefficient of thermal expansion that is within about 60% of a coefficient of thermal expansion of the ceramic component. A gas turbine engine and a method are also disclosed.

Abstract: The present disclosure relates to systems, non-transitory computer-readable media, and methods for generating aspect-based summaries utilizing deep learning. In particular, in one or more embodiments, the disclosed systems access a transcript comprising sentences. The disclosed systems generate, utilizing a sentence classification machine learning model, aspect labels for the sentences of the transcript. The disclosed systems organize the sentences based on the aspect labels. The disclosed systems generate, utilizing a summary machine learning model, a summary of the transcript for each aspect of the plurality of aspects from the organized sentences.

Abstract: A sealing process includes applying a first reactant to a substrate having a porous structure, the first reactant comprising a chromium (III) precursor and a transition metal precursor and applying a second reactant to the first reactant, the second reactant comprising a rare earth element precursor and an alkaline earth element precursor to form reservoirs of trivalent chromium in pore space of the porous structure, and a physical barrier over the substrate and the reservoirs.

Abstract: A method for forming an oxidation protection system on a carbon-carbon composite structure comprises applying a silicone-based slurry to the carbon-carbon composite structure, the silicone-based slurry including metal pigments disposed therein; applying a sealing slurry to the silicone-based slurry; and heating the carbon-carbon composite structure.

Abstract: A method for forming an oxidation protection system on a carbon-carbon composite structure comprises applying a boron slurry to the carbon-carbon composite structure, wherein the boron slurry comprises a boron composition, a first glass compound, a first glass former, a first glass modifier, and a first carrier fluid, the boron composition including a first metal boride, applying a silicon slurry to the carbon-carbon composite structure, wherein the silicon slurry comprises a silicon compound, a glass compound, a second glass former, a second glass modifier, an oxygen inhibitor, and a second carrier fluid; and heating the carbon-carbon composite structure.

Abstract: A method for forming an oxidation protection system on a carbon-carbon composite structure can comprise applying a boron slurry to the carbon-carbon composite structure, wherein the boron slurry comprises a boron compound, a first glass mixture, a first glass former, a first glass modifier, and a first carrier fluid, the first glass mixture including a first glass compound and a second glass compound, the first glass compound having a first viscosity-temperature profile that is at least one order of magnitude below a second viscosity-temperature profile of the second glass compound; applying a silicon slurry to the carbon-carbon composite structure, wherein the silicon slurry comprises a silicon compound, a third glass compound, a second glass former, a second glass modifier, and a second carrier fluid; and heating the carbon-carbon composite structure.

Abstract: A repair process for an article such as an airfoil includes providing an article that has a substrate and a ceramic barrier coating disposed on the substrate, where the ceramic barrier coating has a damaged region, abrading the damaged region to provide dimple in the ceramic barrier coating, wherein a remaining region of the ceramic barrier coating adjacent the dimple remains intact, and depositing a patch of networked ceramic nanofibers in the dimple.

Abstract: A seal system a ceramic component having a surface region defining a first surface roughness, a metallic component situated adjacent the surface region, and a coating system disposed on the surface region. The coating system includes a silicon-containing layer on the surface region and a barrier layer on the silicon-containing layer. The silicon-containing layer has a surface in contact with the barrier layer. The barrier layer has a surface in contact with the metallic component. The surface of the barrier layer has a second surface roughness that is less than the first surface roughness. The barrier layer limits interaction between silicon of the silicon-containing layer and elements of the metallic component. The barrier layer has a coefficient of thermal expansion that is within about 60% of a coefficient of thermal expansion of the ceramic component. A gas turbine engine and a method are also disclosed.

Abstract: A method is disclosed for treating an anodized metal surface. According to the method, polynuclear clusters comprising aluminum oxide hydroxide are applied to the anodized metal surface.

Abstract: A gas turbine engine article includes a silicon-containing ceramic substrate and an environmental barrier coating (EBC) system disposed on the substrate. The EBC system includes, from the substrate, a dense bond coat layer, a porous bond coat layer, and a topcoat layer in contact with the porous bond coat layer. The dense bond coat layer and the porous bond coat layer each include a silica matrix and oxygen-scavenging gas-evolution particles dispersed through the silica matrix. The porous bond coat layer includes engineered pores.

Abstract: A method of making cerium citrate includes combining cerium carbonate and citric acid to produce cerium citrate and carbon dioxide. The cerium citrate is substantially free of negative ions other than citrate. The cerium citrate can be used in a corrosion inhibitor composition.

Abstract: A seal system includes a ceramic component that has a non-core-gaspath surface region that defines a first surface roughness and a core gaspath surface region. A metallic component is situated adjacent the non-core-gaspath surface region. A coating system is disposed on the ceramic component. The coating system includes a silicon-containing layer on the non-core-gaspath surface region and a barrier layer that has a first section on the silicon-containing layer and a second section on the core-gaspath region and that is connected to the first section. The surface of the barrier layer has a second surface roughness that is less than the first surface roughness. The first section is in contact with the metallic component and the second section serves as an environmental barrier on the core-gaspath region.

Abstract: A seal system includes a ceramic component that has a non-core-gaspath surface region that defines a first surface roughness and a core gaspath surface region. A metallic component is situated adjacent the non-core-gaspath surface region. A coating system is disposed on the ceramic component. The coating system includes a silicon-containing layer on the non-core-gaspath surface region and a barrier layer that has a first section on the silicon-containing layer and a second section on the core-gaspath region and that is connected to the first section. The surface of the barrier layer has a second surface roughness that is less than the first surface roughness. The first section is in contact with the metallic component and the second section serves as an environmental barrier on the core-gaspath region.

Abstract: A seal system includes a ceramic component, a metallic component, a silicon-containing layer, and a barrier layer. The ceramic component has a first surface region that defines a first surface roughness. The metallic component is situated adjacent to the first surface region and has a second surface region facing the first surface region. The silicon-containing layer is on the first surface region of the ceramic component and has a contact surface that defines a second surface roughness which is less than the first surface roughness. The barrier layer is on the metallic component and in contact with the silicon-containing layer and serves to limit interaction between silicon of the silicon-containing layer and the metallic component. The barrier layer includes at least one of alumina or MCrAlY.

Abstract: 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.

Abstract: An article includes a substrate, a ceramic barrier coating, and a layer of networked ceramic nanofibers. The ceramic barrier coating is disposed on the substrate and has a porous columnar microstructure. The layer of networked ceramic nanofibers is disposed on the ceramic barrier layer and seals the pores of the porous columnar microstructure.

Abstract: A gas turbine engine article includes a silicon-containing ceramic substrate and an environmental barrier coating (EBC) system disposed on the substrate. The EBC system includes, from the substrate, a dense bond coat layer, a porous bond coat layer, and a topcoat layer in contact with the porous bond coat layer. The dense bond coat layer and the porous bond coat layer each include a silica matrix and oxygen-scavenging gas-evolution particles dispersed through the silica matrix. The porous bond coat layer includes engineered pores.

Abstract: A method is disclosed for treating an anodized metal surface. According to the method, polynuclear clusters comprising aluminum oxide hydroxide are applied to the anodized metal surface.

Abstract: A seal system includes a ceramic component, a metallic component, a coating system. The ceramic component has a first surface region that defines a first surface roughness. The metallic component is situated adjacent to the first surface region and has a second surface region facing the first surface region. The coating system includes a silicon-containing layer on the surface region of the ceramic component and barrier layer on the silicon-containing layer. The silicon containing layer has a surface in contact with the barrier layer and the barrier layer has a surface in contact with the metallic component. The surface of the barrier layer has a second surface roughness that is less than the first surface roughness. The barrier layer serves to limit interaction between silicon of the silicon-containing layer and elements of the metallic component. The barrier layer includes at least one of mullite, zircon, or hafnon.

Abstract: A seal system includes a ceramic component, a metallic component, a silicon-containing layer, and a barrier layer. The ceramic component has a first surface region that defines a first surface roughness. The metallic component is situated adjacent to the first surface region and has a second surface region facing the first surface region. The silicon-containing layer is on the first surface region of the ceramic component and has a contact surface that defines a second surface roughness which is less than the first surface roughness. The barrier layer is on the metallic component and in contact with the silicon-containing layer and serves to limit interaction between silicon of the silicon-containing layer and the metallic component. The barrier layer includes at least one of alumina or MCrAlY.