A sensor element of a gas sensor includes: an element base which is a ceramic structured body including a detection part of detecting a target measurement gas component; and a protective layer which is a porous layer provided in at least a part of an outermost peripheral portion of the element base, wherein in the protective layer, numerous convex parts each having a size of 1.0 μm or less and made up of ceramic microparticles with diameters of 10 nm to 1.0 μm are discretely formed around numerous ceramic coarse grains having diameters of 5.0 μm to 40 μm, the respective ceramic coarse grains are connected to each other directly or via the ceramic microparticle, and a degree of porosity of the protective layer is 5% to 50%.

A foamed lightweight monolithic refractory castable is provided. The castable includes one or more refractory aggregates as a main constituent, one or more foaming additives in a range of 0.1 wt % to 3.0 wt %, one or more cellulosic powder air-entraining additives in a range of 0.005 wt % to 2.0 wt %, one or more binders in a range of 1 wt % to 40 wt %, and one or more superplasticizers in a range of 0.05 wt % to 0.5 wt %. The refractory aggregates include at least one of alumina and silica. The foaming additives include at least one of alkylbenzene sulfonates, alkene sulfonates, and hydroxylalkane sulfates. The superplasticizers include at least one of sodium polyacrylates, naphthalene sulfonates, polyethylene glycols, polycarboxylates, polyacrylates, and polycarboxylate ethers.

A sensor element of a gas sensor includes: an element base which is a ceramic structured body including a detection part of detecting a target measurement gas component; an outer protective layer which is a porous layer provided in at least a part of an outermost peripheral portion of the element base; and an inner protective layer which is a porous layer having a degree of porosity of 30% to 85%, which is larger than a degree of porosity of the outer protective layer, inside the outer protective layer, wherein an average fine pore diameter of the inner protective layer is equal to or larger than 0.5 μm and equal to or smaller than 5.0 μm.

Disclosed is a preform for a ceramic matrix composite including direct channels extending from an exterior surface of the preform to an interior space of the preform wherein the direct channels are free of char.

A ceramic absorber for damping, in particular absorbing, vibrations, in particular combustion vibrations, preferably in gas turbines, which has a foam structure. For the ceramic absorber, the sound absorption capacity is set in a defined way and the efficiency is improved. The foam structure is based on a ceramic powder which contains either a component from the class of silicates or a component from the class of oxides, or a combination of a component from the class of silicates and a component from the class of oxides, and the foam structure has a homogeneous pore distribution.

A recycled aluminium silicate material, suitable for use in ceramic article production, wherein the recycled aluminium silicate material has a particle size distribution such that: (i) the d.sub.50 particle size is from 10 μm to 30 μm; (ii) the d.sub.70 particle size is less than 40 μm; and (iii) the d.sub.98 particle size is less than 60 μm. A particulate mixture, suitable for use in ceramic article production, includes the above defined recycled aluminium silicate material.

A particulate mixture, suitable for use in ceramic article production, wherein the mixture includes from 30 wt % to 80 wt % recycled aluminium silicate material. The particulate mixture has a particle size distribution such that: (i) the d.sub.50 particle size is from 10 μm to 30 μm; (ii) the d.sub.70 particle size is less than 40 μm; and (iii) the d.sub.98 particle size is less than 60 μm.

A process for the production of a ceramic article includes the steps of: (a) preparing a particulate mixture; (b) contacting the particulate mixture to water to form a humidified mixture; (c) pressing the humidified mixture to form a green article; (d) optionally, subjecting the green article to an initial drying step; (e) optionally, glazing the green article to form a glazed green article; (f) subjecting the green article to a heat treatment step to form a hot fused article; and (g) cooling the hot fused article to form a glazed ceramic article. The particulate mixture includes from 30 wt % to 80 wt % recycled aluminium silicate material. The particulate mixture has: (i) a d.sub.50 particle size from 10 μm to 30 μm; (ii) a d.sub.70 particle size of less than 40 μm; and (iii) a d.sub.98 particle size of less than 60 μm. Steps (c) and (f), and optionally steps (d) and (e) are continuous process steps.

A chromia-based brick, having chromia as a main component, includes: 70 to 95 mass % of Cr.sub.2O.sub.3; 0.5 to 15 mass % of ZrO.sub.2; 0.4 to 4.0 mass % of P.sub.2O.sub.5 derived from phosphate added as raw material; 10 or lower mass % of Al.sub.2O.sub.3; and a sintering aid component and unavoidable components.

The present invention provides an annealing separator composition, a grain-oriented electrical steel sheet and a method for manufacturing a grain-oriented electrical steel sheet.

An annealing separator composition for a grain-oriented electrical steel sheet according to an embodiment of present invention comprising: on the basis of total solid 100 wt %, 5 to 70 wt % of mullite; and the remainder being magnesium oxide or magnesium hydroxide.