Disclosed herein are embodiments of composite hexagonal ferrite materials formed from a combination of Y phase and Z phase hexagonal ferrite materials. Advantageously, embodiments of the material can have a high resonant frequency as well as a high permeability. In some embodiments, the materials can be useful for magnetodielectric antennas.

A powder material for an air electrode in a solid oxide fuel cell, the powder material being a powder of a metal composite oxide having a perovskite crystal structure represented by:

A1.sub.1-xA2.sub.xBO.sub.3-δ, where the element A1 is at least one selected from the group consisting of La and Sm, the element A2 is at least one selected from the group consisting of Ca, Sr, and Ba, the element B is at least one selected from the group consisting of Mn, Fe, Co, and Ni, x satisfies 0<x<1, and δ is an oxygen deficiency amount. The powder has a specific surface area of 20 m.sup.2/g or more, satisfies (Crystallite diameter/Specific surface area-based particle diameter)≥0.3, and contains elements M in an amount of 300 ppm or less in terms of atoms, the elements M being other than the elements A1, A2 and B, and oxygen.

A solid-state fuel battery comprises an anode, a cathode spaced from the anode, and a solid-state electrolyte disposed between the anode and the cathode. A material of the solid-state electrolyte is a hydrogen-containing transition metal oxide having a structural formula of ABO.sub.xH.sub.y, wherein A is one or more of alkaline earth metal elements and rare-earth metal elements, B is one or more of transition metal elements, x is a numeric value in a range of 1 to 3, and y is a numeric value in a range of 0 to 2.5. A method for making the solid-state electrolyte for the solid-state fuel battery is further provided in the present disclosure.

A sintered ferrite magnet having a composition of metal elements of Ca, R, A, Fe and Co, which is represented by the general formula of Ca.sub.1−x−yR.sub.xA.sub.yFe.sub.2n−zCo.sub.z, wherein R is at least one of rare earth elements indispensably including La; A is Sr and/or Ba; x, y, z and n represent the atomic ratios of Ca, R, A, Fe and Co; 2n represents a molar ratio expressed by 2n=(Fe+Co)/(Ca+R+A); and x, y, z and n meet the conditions of 0.15≤x≤0.35, 0.05≤y≤0.40, (1−x−y)>y, 0<z≤0.18, and 7.5≤(2n−z)<11.0.

A method for ammonia decomposition to produce hydrogen, the method comprising the steps of introducing an ammonia stream to a reactor, wherein the ammonia stream comprises ammonia, wherein the reactor comprises a cobalt-based catalyst, the cobalt-based catalyst comprising 15 wt % and 70 wt % of cobalt, 5 wt % and 45 wt % of cerium, and 0.4 wt % and 0.5 wt % barium, wherein a remainder of weight of the cobalt-based catalyst is oxygen; contacting the ammonia in the ammonia stream with the cobalt-based catalyst, wherein the cobalt-based catalyst is operable to catalyze an ammonia decomposition reaction; catalyzing the ammonia decomposition reaction to cause the ammonia decomposition in the presence of the cobalt-based catalyst to produce hydrogen; and withdrawing a product stream from the reactor, the product stream comprising hydrogen.

A method for ammonia decomposition to produce hydrogen, the method comprising the steps of introducing an ammonia stream to a reactor, wherein the ammonia stream comprises ammonia, wherein the reactor comprises a cobalt-based catalyst, the cobalt-based catalyst comprising 15 wt % and 70 wt % of cobalt, 5 wt % and 45 wt % of cerium, and 0.4 wt % and 0.5 wt % barium, wherein a remainder of weight of the cobalt-based catalyst is oxygen; contacting the ammonia in the ammonia stream with the cobalt-based catalyst, wherein the cobalt-based catalyst is operable to catalyze an ammonia decomposition reaction; catalyzing the ammonia decomposition reaction to cause the ammonia decomposition in the presence of the cobalt-based catalyst to produce hydrogen; and withdrawing a product stream from the reactor, the product stream comprising hydrogen.

Provided is a novel compound which can be used for positive-electrode catalysts of metal-air batteries. The melilite-type complex oxide according to the present invention is represented by a general formula (BazSr1−z)2CoxFe2−2x(SiyGe1−y)1+xO7 (in the formula, 0≤x≤1, 0≤y≤1, and 0≤z≤1, excluding the case where x=1, y=1, and z=0, the case where x=1, y=1, and z=1, the case where x=1, y=0, and z=0, the case where x=1, y=0, and z=1, the case where x=0, y=0, and z=0, and the case where x=0, y=0, and z=1).

This ferrite sintered magnet comprises metallic elements at an atomic ratio represented by formula (1):
Ca.sub.1-w-xR.sub.wSr.sub.xFe.sub.zCo.sub.m  (1) in formula (1), R is at least one element selected from the group consisting of rare-earth elements and Bi, and R comprises at least La, in formula (1), w, x, z and m satisfy formulae (2) to (5):
0.360≤w≤0.420  (2)
0.110≤x≤0.173  (3)
8.51≤z≤9.71  (4)
0.208≤m≤0.269  (5), and in a section parallel to an axis of easy magnetization, when the number of total ferrite grains is N and the number of ferrite grains having a stacking fault is n, 0≤n/N≤0.20 is satisfied.

The invention relates to a method for preparing a composite metal oxide hollow fibre. A certain stoichiometry of composite metal oxide raw material and a polymer binding agent are added to an organic solvent, and mixed mechanically to obtain an evenly dispersed spinning solution having a suitable viscosity. After defoaming treatment, the spinning solution is extruded through a spinneret and, after undergoing a certain dry spinning process, enters an external coagulation bath; during this period, a phase inversion process occurs and composite metal oxide hollow fibre blanks are formed. The blanks are immersed in the external coagulation bath and the organic solvent is displaced; after natural drying, the blanks undergo a heat treatment process; during this period, polymer burn off, in situ reaction, and in situ sintering processes occur to obtain the composite metal oxide hollow fibre.

This ferrite magnet has a ferrite phase having a magnetoplumbite structure, and an orthoferrite phase, and is characterized in that the composition ratios of the total of each metal element A, R, Fe and Me is represented by expression (1) A.sub.1-xR.sub.x(Fe.sub.12-yMe.sub.y).sub.z, (in expression (1), A is at least one element selected from Sr, Ba, Ca and Pb; R is at least one element selected from the rare-earth elements (including Y) and Bi, and includes at least La, and Me is Co, or Co and Zn) and in that the content (m) of the orthoferrite phase is 0<m<28.0 in mol %. The invention makes it possible to achieve a ferrite magnet with increased Br.