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.

A porous refractory cast material contains a closed refractory aggregate fraction having a minimum particle size and a maximum particle size; the ratio of maximum particle size to minimum particle size is 10:1 or less. This closed refractory aggregate fraction comprises all of the porous refractory cast material having a particle diameter greater than 0.1 mm. The porous refractory cast material also contains a binder phase containing refractory selected from calcium aluminate cement, alumina phosphate, hydratable alumina, colloidal silica and combinations thereof. Also disclosed is a metallurgical vessel with an interior lining incorporating the porous refractory cast material.

A porous refractory cast material contains a closed refractory aggregate fraction having a minimum particle size and a maximum particle size; the ratio of maximum particle size to minimum particle size is 10:1 or less. This closed refractory aggregate fraction comprises all of the porous refractory cast material having a particle diameter greater than 0.1 mm. The porous refractory cast material also contains a binder phase containing refractory selected from calcium aluminate cement, alumina phosphate, hydratable alumina, colloidal silica and combinations thereof. Also disclosed is a metallurgical vessel with an interior lining incorporating the porous refractory cast material.

A refractory object can include at least 10 wt % Al.sub.2O.sub.3. Further, the refractory object may contain less than approximately 6 wt % SiO.sub.2 or may include a dopant that includes an oxide of Ti, Mg, Ta, Nb, or any combination thereof. In an embodiment, at least approximately 1% of the Al.sub.2O.sub.3 in the refractory object can be provided as reactive Al.sub.2O.sub.3. In another embodiment, the refractory object may have a density of at least approximately 3.55 g/cc, a corrosion rate of no greater than approximately 2.69 mm/year, or any combination of the foregoing. In a particular embodiment, the refractory object can be used to form an Al—Si—Mg glass sheet. In an embodiment, the refractory object may be formed by a process using a compound of Ti, Mg, Ta, Nb, or any combination thereof.

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 refractory composition for forming a working lining in a metallurgical vessel contains a coarse-grain refractory particle fraction and a fine-grain refractory particle fraction, or at least 0.25% additive calcium oxide, or at least 0.25% titanium dioxide. The coarse-grain refractory particles can include alumina particles, magnesia particles, magnesium aluminate spinel particles, zirconia particles, or doloma particles, or a combination of any of these particles. The fine-grain refractory particles can be comprised of any low-magnesia refractory oxide. The refractory composition can be applied to a metallurgical vessel by spraying, gunning, shotcreting, vibrating, casting, troweling, or positioning preformed refractory shapes, or a combination of any of these techniques. When contacted by molten metal, the molten metal penetrates into the refractory material, wetting the coarse-grain refractory particles, and forming a refractory-metal composite barrier layer that decreases or blocks oxygen transport through the refractory lining.

Disclosed are ceramic bodies comprised of composite cordierite-mullite-aluminum magnesium titanate (CMAT) ceramic compositions having high cordierite-to-mullite ratio and methods for the manufacture of same.

A guide member for a fishing line including an alumina ceramic including Ti and Al, a content of Ti being not less than 0.5 mass % in terms of TiO.sub.2, a content of Al being not less than 92 mass % in terms of Al.sub.2O.sub.3, and a main phase of the alumina ceramic being alumina crystals, wherein a content ratio of aluminas crystal with an aspect ratio of not less than 2 within the alumina crystals is not less than 15%.

A composition for a heat treatment jig includes: alumina at a weight ratio within the range of 5% or more and 25% or less; mullite at a weight ratio within the range of 0% or more and 35% or less; cordierite at a weight ratio within the range of 15% or more and 35% or less; spinel at a weight ratio within the range of 0% or more and 35% or less; and fused silica at a weight ratio within the range of 15% or more and 50% or less. The composition for a heat treatment jig is used for the method of manufacturing a heat treatment jig, such as a heat treatment container.

A synthetic titanium-corundum composite includes a titanium alloy and a coherently bonded corundum phase. The titanium alloy includes at least one elemental titanium solid solution and the atomic percentage of aluminum in the titanium alloy ranges from 0.5% to 24.5%.