A preparation method for an yttrium aluminum garnet continuous fiber. The method prepares a spinnable precursor sol by utilizing an Al.sub.13 colloidal particles contained alumina sol, γ-AlOOH nano-dispersion, yttria sol, glacial acetic acid and polyvinylpyrrolidone, then prepares a gel continuous fiber by adopting a dry spinning technique, and carries out a heat treatment to obtain the yttrium aluminum garnet continuous fiber.

Doped cerium oxide particles may comprise about 90 weight percent (wt. %) to about 99.9 wt. % cerium oxide (CeO.sub.2) and up to about 10 wt. % dopant. Exemplary doped cerium oxide particles may have a BET specific surface area of more than 150 m.sup.2/g after calcination at 500° C. for 8 hours. Exemplary doped cerium oxide particles may have an oxygen storage capacity (OSC) of more than 900 μmol.Math.O.sub.2/g after calcination at 500° C. for 8 hours.

A paramagnetic garnet-type transparent ceramic characterized by being a sintered body of a terbium-containing composite oxide represented by formula (1) in which the linear transmittance at a wavelength of 1,064 nm at an optical path length of 15 mm is 83% or higher.
(Tb.sub.1-x-ySc.sub.xCe.sub.y).sub.3(Al.sub.1-zSc.sub.z).sub.5O.sub.12  (1)
(In the formula, 0<x<0.08, 0≤y≤0.01, 0.004<z<0.16.)

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.

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.

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.

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.

The invention relates to a process for preparing aluminates of the general formula (I)

A.sub.1B.sub.xAl.sub.12-xO.sub.19-y where A is at least one element from the group consisting of Sr, Ba and La, B is at least one element from the group consisting of Mn, Fe, Co, Ni, Rh, Cu and Zn, x=0.05-1.0, y is a value determined by the oxidation states of the other elements, which comprises the steps (i) provision of one or more solutions or suspensions comprising precursor compounds of the elements A and B and also a precursor compound of aluminum in a solvent, (ii) conversion of the solutions or suspensions or the solutions into an aerosol, (iii) introduction of the aerosol into a directly or indirectly heated pyrolysis zone, (iv) carrying out of the pyrolysis and (v) separation of the resulting particles comprising hexaaluminate of the general formula (I) from the pyrolysis gas.

A method of inhibiting an irregular aggregation of a nanosized powder includes (A) providing a nanosized ceramic powder to perform thereon a thermal analysis and thereby attain an endothermic peak temperature; (B) performing an impurity-removal heat treatment on the nanosized ceramic powder at a temperature higher than the endothermic peak temperature; (C) switching the nanosized ceramic powder from a temperature environment of the impurity-removal heat treatment to an environment of a temperature higher than a phase change temperature of the nanosized ceramic powder, followed by performing a calcination heat treatment on the nanosized ceramic powder in the environment of the temperature higher than the phase change temperature of the nanosized ceramic powder, wherein the nanosized ceramic powder skips the temperature environment between impurity-removal heat treatment and calcination heat treatment to shun generating a vermicular structure, avoid crystalline irregularity and abnormal growth, reduce particle aggregation, and achieve satisfactory distribution.

A method of manufacturing a conversion element is disclosed. A precursor material is selected from one or more of lutetium, aluminum and a rare-earth element. The precursor material is mixed with a binder and a solvent to obtain a slurry. A green body is formed from the slurry and the green body is sintered to obtain the conversion element. The sintering is performed at a temperature of more than 1720° C.