An article comprises a substrate comprising a ceramic matrix composite; a first layer disposed over the substrate, the first layer comprising an interconnected first silicide, and a second phase; and a second layer disposed over the first layer, the second layer comprising a second silicide in mass transfer communication with the first silicide.

An article includes a silicon-containing ceramic substrate and a coating system overlying the silicon-containing ceramic substrate. The coating system includes an intermediate coating overlying the silicon-containing ceramic substrate and a barrier coating overlying the intermediate coating. The intermediate coating includes silicon and hafnium disilicide. A coefficient of thermal expansion of the intermediate coat is less than about 7 parts per million (ppm) per degree Kelvin (K).

A method of forming a -SiC material or coating by mixing SiO.sub.2 with carbon and heating the mixture in vacuum wherein the carbon is oxidized to CO gas and reduces the SiO.sub.2 to SiO gas and reacting a carbon material with the SiO gas at a temperature in the range of 1300 to 1600 C. resulting in a SiC material or a SiC coating on a substrate. Also disclosed is the related SiC material or coating prepared by this method.

A method of forming a -SiC material or coating by mixing SiO.sub.2 with carbon and heating the mixture in vacuum wherein the carbon is oxidized to CO gas and reduces the SiO.sub.2 to SiO gas and reacting a carbon material with the SiO gas at a temperature in the range of 1300 to 1600 C. resulting in a SiC material or a SiC coating on a substrate. Also disclosed is the related SiC material or coating prepared by this method.

The disclosure provides for an article including a substrate, an environmental barrier coating (EBC), a bondcoat and a boron source. The substrate may include a silicon-including ceramic material. The EBC may be disposed over the substrate, and the bondcoat may disposed between the substrate and the EBC. The bondcoat may include silicon. The boron source may be disposed within the article to provide an effective amount of boron to form an oxide including silicon and at least 0.1 weight percent boron during exposure of the bondcoat to an oxidizing environment at a temperature greater than 900 degrees Celsius. The oxide may be a borosilicate glass that is substantially devitrification resistant to prevent spallation of the EBC and thereby enhance the temperature capability of the article.

The disclosure provides for an article including a substrate, an environmental barrier coating (EBC), a bondcoat and a boron source. The substrate may include a silicon-including ceramic material. The EBC may be disposed over the substrate, and the bondcoat may disposed between the substrate and the EBC. The bondcoat may include silicon. The boron source may be disposed within the article to provide an effective amount of boron to form an oxide including silicon and at least 0.1 weight percent boron during exposure of the bondcoat to an oxidizing environment at a temperature greater than 900 degrees Celsius. The oxide may be a borosilicate glass that is substantially devitrification resistant to prevent spallation of the EBC and thereby enhance the temperature capability of the article.

A modifying agent of an alkaline electrolyzed water. A substance being supplied to a concrete structure in order to produce calcium silicate for repairing concrete and including an alkali metal silicate is defined as a concrete protective agent. The modifying agent is supplied to the concrete structure in advance of the supply of the concrete protective agent. The alkali metal silicate and the calcium ion included in the concrete protective agent contribute to the production of the calcium silicate. A method for repairing a concrete structure includes supplying the concrete protective agent to the concrete structure and supplying a modifying agent for a concrete structure including an alkaline electrolyzed water to the concrete structure, the step of supplying a modifying agent being performed before the step of supplying the concrete protective agent to promote production of the calcium silicate in the step of supplying the concrete protective agent.

A modifying agent of an alkaline electrolyzed water. A substance being supplied to a concrete structure in order to produce calcium silicate for repairing concrete and including an alkali metal silicate is defined as a concrete protective agent. The modifying agent is supplied to the concrete structure in advance of the supply of the concrete protective agent. The alkali metal silicate and the calcium ion included in the concrete protective agent contribute to the production of the calcium silicate. A method for repairing a concrete structure includes supplying the concrete protective agent to the concrete structure and supplying a modifying agent for a concrete structure including an alkaline electrolyzed water to the concrete structure, the step of supplying a modifying agent being performed before the step of supplying the concrete protective agent to promote production of the calcium silicate in the step of supplying the concrete protective agent.

The present disclosure generally relates to materials, processes, generators, and/or systems, for generating radioisotope. The present disclosure also generally relates to ceramic materials comprising radioisotope suitable for use in a radioisotope generator. The present disclosure also generally relates to processes, generators and/or systems, for producing and capturing radioisotope. The present disclosure also generally relates to the preparation of radioisotope solutions for use in radiopharmacy and/or other clinical applications.

An article includes a silicon-containing region; at least one outer layer overlying a surface of the silicon-containing region; and a constituent layer on the surface of the silicon-containing region and between and contacting the silicon-containing region and the at least one outer layer, the constituent layer being formed by constituents of the silicon-containing region and being susceptible to creep within an operating environment of the article, wherein the silicon-containing region defines a plurality of channels and a plurality of ridges that interlock within the plurality of channels are formed in the silicon-containing region to physically interlock the at least one outer layer with the silicon-containing region through the constituent layer.