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.

The invention relates to a method for manufacturing of a sinterable green body from sodium-β-aluminate- and/or precursor-particles bonded via binders by means of slip casting, wherein a castable slip containing the particles as well as dispersants and binders is introduced into a casting mold and, after solidification, is demolded as a green body.

The invention relates to a method for manufacturing of a sinterable green body from sodium-β-aluminate- and/or precursor-particles bonded via binders by means of slip casting, wherein a castable slip containing the particles as well as dispersants and binders is introduced into a casting mold and, after solidification, is demolded as a green body.

A method for making yttrium aluminum garnet (YAG) nanopowders, includes mixing carbohydrate and organic amine in a container according to a first ratio, stirring the carbohydrate and organic amine in the container under a heating condition for 2 minutes to 120 minutes for melting the carbohydrate and the organic amine to obtain a clear and transparent mixed solution, adding yttrium salt and aluminum salt at a second ratio to the clear and transparent mixed solution, and stirring the yttrium salt, the aluminum salt, and the clear and transparent mixed solution in the container under the heating condition for 5 minutes to120 minutes to form a uniform molten mixture, heating the uniform molten mixture to dehydrate and carbonize the carbohydrate to obtain a dark brown fluffy solid, and performing a heat treatment on the dark brown fluffy solid at 800° C. to 1500° C. to obtain the YAG nanopowders.

It is described a process for producing transparent ceramic bodies with at least two zones having different garnet composition, in particular in which one of said zones has composition Y.sub.3AI.sub.5O.sub.12. The invention is especially useful for the production of transparent ceramic bodies having preset complex shapes and/or a controlled complex distribution of doping ions.

A powder for coating or sintering exhibits a peak assigned to orthorhombic YAlO.sub.3 in an X-ray diffractometry. Of peaks exhibited in the X-ray diffractometry, the peak assigned to the (112) plane of orthorhombic YAlO.sub.3 is a peak that has the highest peak intensity. Preferably, the value of the ratio of S2 to S1, S2/S1, is less than 1 in an X-ray diffractometry using CuKα radiation, where SI represents the peak intensity of the peak assigned to the (112) plane of orthorhombic YAlO.sub.3 and S2 represents the peak intensity of the peak assigned to the (104) plane of trigonal Al.sub.2O.sub.3.

Embodiments are directed to the field of ceramics and relate to electron-emitting ceramics such as those which can be used as cathode material for electron emissions in space flight systems, for example. Embodiments specify an electron-emitting ceramic which has an improved temperature conductivity with a simultaneously continuous electron emission. The electron-emitting ceramic contains at least>70 vol. % C12A7 electride and a proportion of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, In, Sn, Sb, Te, Tl, Pb, or Bi as metal and/or with Ti, wherein the proportion of the metals lies between>0 and<30 vol. %, and the ceramic has a density of at least 85% of the theoretical density of the ceramic and the ceramic contains 0 to maximally 10 vol. % production-specific impurities.

Embodiments are directed to the field of ceramics and relate to electron-emitting ceramics such as those which can be used as cathode material for electron emissions in space flight systems, for example. Embodiments specify an electron-emitting ceramic which has an improved temperature conductivity with a simultaneously continuous electron emission. The electron-emitting ceramic contains at least>70 vol. % C12A7 electride and a proportion of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, In, Sn, Sb, Te, Tl, Pb, or Bi as metal and/or with Ti, wherein the proportion of the metals lies between>0 and<30 vol. %, and the ceramic has a density of at least 85% of the theoretical density of the ceramic and the ceramic contains 0 to maximally 10 vol. % production-specific impurities.

A method for improving the insulating character/and or penetration resistance of a surface comprising lining a surface of a lime kiln, a cement kiln, a roasting kiln, a thermal oxidizer, or a fluidized bed reactor that is subject to wear by an alkali environment and/or an alkaline environment with a refractory composition comprising a refractory aggregate consisting essentially of a calcium hexa aluminate clinker having the formula CA.sub.6, wherein C is equal to calcium oxide, wherein A is equal to aluminum oxide, and wherein the hexa aluminate clinker has from zero to less than about fifty weight percent C.sub.12A.sub.7, and wherein greater than 98 weight percent of the calcium hexa aluminate clinker having a particle size ranging from −20 microns to +3 millimeters, for forming a liner of the surface.