A porous material includes an aggregate in which oxide films are formed on surfaces of particle bodies, and a binding material that contains cordierite and binds the aggregate together in a state where pores are formed. The binding material or the oxide films contain a rare-earth component that excludes Ce.

A container for heat treatment of a positive-electrode active material for a lithium-ion battery to the present invention is characterized by having a base portion containing 60 to 95 mass % of alumina, and a surface portion containing 20 to 80 mass % of spinel and formed integrally with the base portion. Moreover, a production method of the present invention is characterized by comprising a step of placing an alumina-based powder, a step of placing a spinel-based powder above the alumina-based powder, a step of forming a compact by compressing the powders and a step of firing the compact.

A method for preparing an infrared radiation ceramic material includes mixing and ball milling raw materials of Fe.sub.2O.sub.3, MnO.sub.2 and CuO in a mass ratio to obtain a mixed powder; pressing the mixed powder; adjusting laser spot, laser power and laser sintering time of a laser; irradiating or sintering by a first laser the pressed mixed powder in a crucible for a high-temperature solid-phase reaction to obtain an AB.sub.2O.sub.4 type ferrite powder; obtaining a first mixture by mixing the AB.sub.2O.sub.4 type ferrite powder and a cordierite powder in a mass ratio; adding a sintering aid and a nucleating agent for ball milling; obtaining a second mixture by mixing the first mixture and a binder for aging; pressing the second mixture; and irradiating or sintering the pressed second mixture by a second laser to obtain the infrared radiation ceramic material.

In an X-ray diffraction diagram of a cordierite sintered body of the present invention, the ratio of the total of the maximum peak intensities of components other than cordierite components to the peak top intensity of the (110) plane of cordierite is 0.0025 or less. Since having a significantly small amount of different phases other than the cordierite components, this cordierite sintered body has a high surface flatness when the surface thereof is mirror-polished.

A cordierite-based sintered body according to the present invention contains cordierite as a main component and silicon nitride or silicon carbide. The cordierite-based sintered body preferably has a thermal expansion coefficient less than 2.4 ppm/° C. at 40° C. to 400° C., an open porosity of 0.5% or less, and an average grain size of 1 μm or less.

The present invention relates to nuclear fuel pellets and a manufacturing method thereof, and more particularly, to nuclear fuel pellets comprising a trapping material of fission gas and a manufacturing method thereof. A nuclear fuel pellet of the present invention comprises a nuclear fuel; and a trapping material of fission gas, wherein the trapping material of the fission gas includes an oxide containing at least one element selected from the group consisting of silicon (Si), aluminum (Al) and barium (Ba) to exhibit an excellent trapping ability selective and independent for fission gas.

A porous material includes an aggregate, and a binding material that binds the aggregate together in a state where pores are formed. The porous material contains 0.1 to 10.0 mass % of an MgO component, 0.5 to 25.0 mass % of an Al.sub.2O.sub.3 component, and 5.0 to 45.0 mass % of an SiO.sub.2 component with respect to the mass of the whole porous material, and further contains 0.01 to 5.5 mass % of an Sr component in terms of SrO.

A honeycomb structure has a plurality of cells formed by a plurality of partition walls. The partition walls are formed of a porous material composed predominantly of cordierite. Each partition wall includes surface layer portions having a porosity of 50% or more and an inside portion having a porosity of 50% or more, the surface layer portions being portions ranging respectively from opposite surfaces to a depth corresponding to 25% of the thickness of the partition wall, and the inside portion being the other portion. The surface layer portions and the inside portion both include pores having axial pore widths of less than 30 μm and pores having axial pore widths of 30 μm or more. A mean axial pore width in the surface layer portions is smaller than a mean axial pore width in the inside portion.

A honeycomb structure including: a honeycomb structure body having porous partition walls which define a plurality of cells extending from an inflow end face to an outflow end face to form through channels for a fluid, and a first circumferential wall which is disposed in at least a part of a circumference of the partition walls, and a second circumferential wall disposed to surround an outer side of the honeycomb structure body, wherein the honeycomb structure body does not have an interface between the partition walls and the first circumferential wall, and in a face perpendicular to an extending direction of the cells, a maximum thickness of the first circumferential wall is from 0.1 to 0.3 mm.

Sintered bead that has a crystalline composition, as percentages by weight based on the total weight of the crystalline phases: zircon<25%; 50%≤cubic zirconia+tetragonal zirconia≤95%, the cubic zirconia content being greater than 50%, the cubic zirconia content being the (cubic zirconia/(cubic zirconia+tetragonal zirconia) ratio by weight); 0≤monoclinic zirconia≤(10−0.2*tetragonal zirconia) %; 5%≤corundum≤50%; crystalline phases other than zircon, cubic zirconia, tetragonal zirconia, monoclinic zirconia and corundum<10%; and the following chemical composition, as percentages by weight based on the oxides: 34%≤ZrO.sub.2+HfO.sub.2, ZrO.sub.2+HfO.sub.2 being the remainder to 100%; HfO.sub.2≤4.0%; 0.5%≤SiO.sub.2≤14.1%; 4.5%≤Al.sub.2O.sub.3≤49.6%; 2.75%≤Y.sub.2O.sub.3≤22.8%; MgO≤5%; CaO≤2%; oxides other than ZrO.sub.2, HfO.sub.2, SiO.sub.2, Al.sub.2O.sub.3, MgO, CaO and Y.sub.2O.sub.3<5.0%.