Provided is a refractory product which is not impregnated with pitch or the like, wherein it has higher corrosion-erosion resistance and thermal shock resistance as compared to a refractory product subjected to pitch or the like-impregnation treatment. The refractory product which is not impregnated with tar or pitch is characterized in that, in terms of values of physical properties of a sample of the refractory product as measured after heat-treating the sample in a non-oxidizing atmosphere at 1200° C.: an apparent porosity is 7% or less; a total void volume of pores having a pore diameter of 1 μm or less is 80% or more of an integrated void volume of pores of the entire sample of the refractory product; and a gas permeability is 50×10.sup.−17 m.sup.2 or less.

Systems and methods for forming an oxidation protection system on a composite structure are provided. In various embodiments, the oxidation protection system comprises a boron-glass layer formed on the composite substrate and a silicon-glass layer formed over the boron-glass layer. Each of the boron-glass layer and the silicon-glass layer includes a glass former.

A ceramic matrix composite includes a substrate which contains a fibrous body made of silicon carbide fiber, and a matrix which is formed in the substrate, and which contains silicon carbide and a silicon material made of silicon or a binary silicon alloy.

The present invention provides a high alumina fused cast refractory that is easily produced and has low porosity and high corrosion resistance, and a method of producing the same. The high alumina fused cast refractory of the present invention has the following chemical composition: 95.0 mass % to 99.5 mass % Al.sub.2O.sub.3, 0.20 mass % to 1.50 mass % SiO.sub.2, 0.05 mass % to 1.50 mass % B.sub.2O.sub.3, 0.05 mass % to 1.20 mass % MgO and balance. The method of producing the high alumina fused cast refractory of the present invention includes obtaining a mixture by mixing an Al.sub.2O.sub.3 source material, a SiO.sub.2 source material, a B.sub.2O.sub.3 source material and an MgO source material, and fusing the mixture.

An automated preparation method of a SiC.sub.f/SiC composite flame tube, comprising the following steps: preparing an interface layer for a SiC fiber by a chemical vapor infiltration process, and obtaining the SiC fiber with a continuous interface layer; laying a unidirectional tape on the SiC fiber with the continuous interface layer and winding the SiC fiber with the continuous interface layer to form and obtaining a preform of a net size molding according to a fiber volume and a fiber orientation obtained in a simulation calculation; and adopting a reactive melt infiltration process and the chemical vapor infiltration process successively for a densification and obtaining a high-density SiC.sub.f/SiC composite flame tube in a full intelligent way. The SiC.sub.f/SiC composite flame tube prepared by the present disclosure not only has a high temperature resistance, but also has a low thermal expansion coefficient, high thermal conductivity and high thermal shock resistance.

An environmental barrier coating, comprising a substrate containing silicon; an environmental barrier layer applied to the substrate; the environmental barrier layer comprising an oxide matrix; an oxidant getter phase interspersed throughout the oxide matrix; and a self-healing phase interspersed throughout the oxide matrix.

Disclosed are an anti-corrosion and anti-coking ceramic coating with easy state identification for a coal-fired boiler and a preparation method thereof. The ceramic coating is formed by compounding a bottom coating layer and a surface coating layer, wherein the bottom coating layer is prepared from raw materials comprising sodium silicate, lanthanum oxide, niobium pentoxide, aluminum oxide, bismuth oxide, boron oxide, zinc oxide, silicon oxide, titanium dioxide, nano whisker, titanium nitride, and graphite fluoride, and the surface coating layer is prepared from raw materials comprising sodium silicate, lanthanum oxide, niobium pentoxide, chromium oxide, aluminum oxide, bismuth oxide, boron oxide, zinc oxide, silicon oxide, graphite fluoride, titanium nitride, silicon carbide, nano whisker, and cobalt green. An operating state of the ceramic coating is rapidly identified by a color difference between the bottom coating layer and the surface coating layer, which is beneficial to efficient maintenance of the ceramic coating during inspection.

In one aspect, the disclosure relates to nanocomposite radome materials incorporating boron nitride materials in a polymer derived ceramic matrix. In another aspect, the nanocomposite radome materials have superior electrochemical performance, excellent mechanical strength and stability, corrosion resistance and transparency to electromagnetic radiation, methods of making the same, and articles and components incorporating the same. In one aspect, the nanocomposite radome materials retain functionality in the presence of significant amounts of moisture. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.

Provided is a C/C composite having a long life in an environment including a heating process and a cooling process and having less adverse effects on surrounding facilities and the quality of treatment objects. A C/C composite in which, in measurement for open pores by mercury porosimetry, an open porosity for open pores with a radius of not less than 0.4 μm and less than 10 μm in the C/C composite is 2.0% or less.

A method for forming an oxidation protection system on a composite structure may comprise: applying a ceramic layer slurry to the composite structure, wherein the ceramic layer slurry comprises aluminum and silicon in a solvent or carrier fluid; and heating the composite structure in an environment comprising nitrogen gas and oxygen gas to form a ceramic layer on the composite structure, wherein the ceramic layer comprises aluminum nitride and alumina.