Provided is a ferrite sintered magnet including a ferrite phase having a magnetoplumbite-type crystal structure. x, y, and m satisfy the following Equations (1), (2), and (3) when composition of the ferrite sintered magnet is represented by R.sub.1-xA.sub.xFe.sub.m-yCo.sub.y, where R denotes at least one kind of element selected from rare earth elements including Y and A denotes Ca or Ca and elements including at least one kind selected from Sr or Ba. The content of B in the ferrite sintered magnet is from 0.1% to 0.6% by mass in terms of B.sub.2O.sub.3.

0.2≤x≤0.8  (1)

0.1≤y≤0.65  (2)

3≤m≤14  (3)

Provided is a ferrite sintered magnet including a ferrite phase having a magnetoplumbite-type crystal structure. x, y, and m satisfy the following Equations (1), (2), and (3) when composition of the ferrite sintered magnet is represented by R.sub.1-xA.sub.xFe.sub.m-yCo.sub.y, where R denotes at least one kind of element selected from rare earth elements including Y and A denotes Ca or Ca and elements including at least one kind selected from Sr or Ba. The content of B in the ferrite sintered magnet is from 0.1% to 0.6% by mass in terms of B.sub.2O.sub.3.

0.2≤x≤0.8  (1)

0.1≤y≤0.65  (2)

3≤m≤14  (3)

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 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.

The present invention relates to a method for producing a magnetic powder, including: preparing a precursor solution containing an iron precursor and a silica precursor; spraying the precursor solution to form iron/silica precursor droplets; drying the iron/silica precursor droplets to produce iron/silica precursor particles; and heat treating the iron/silica precursor particles to produce an iron oxide/silica composite powder in which iron oxide particles are embedded in a silica matrix. The present invention also relates to a magnetic powder produced by the method. The present invention may provide an iron oxide magnetic powder that does not use rare earth elements and a method for producing the same.

The present invention relates to a method for producing a magnetic powder, including: preparing a precursor solution containing an iron precursor and a silica precursor; spraying the precursor solution to form iron/silica precursor droplets; drying the iron/silica precursor droplets to produce iron/silica precursor particles; and heat treating the iron/silica precursor particles to produce an iron oxide/silica composite powder in which iron oxide particles are embedded in a silica matrix. The present invention also relates to a magnetic powder produced by the method. The present invention may provide an iron oxide magnetic powder that does not use rare earth elements and a method for producing the same.

Provided is a ferrite sintered magnet including a ferrite phase having a magnetoplumbite-type crystal structure. x, y, and m satisfy the following Equations (1), (2), and (3) when composition of the ferrite sintered magnet is represented by R.sub.1-xA.sub.xFe.sub.m-yCo.sub.y, where R denotes at least one kind of element selected from rare earth elements including Y and A denotes Ca or Ca and elements including at least one kind selected from Sr or Ba. The content of B in the ferrite sintered magnet is from 0.1% to 0.6% by mass in terms of B.sub.2O.sub.3.
0.2≤x≤0.8  (1)
0.1≤y≤0.65  (2)
3≤m<14  (3)

Provided is a ferrite sintered magnet including a ferrite phase having a magnetoplumbite-type crystal structure. x, y, and m satisfy the following Equations (1), (2), and (3) when composition of the ferrite sintered magnet is represented by R.sub.1-xA.sub.xFe.sub.m-yCo.sub.y, where R denotes at least one kind of element selected from rare earth elements including Y and A denotes Ca or Ca and elements including at least one kind selected from Sr or Ba. The content of B in the ferrite sintered magnet is from 0.1% to 0.6% by mass in terms of B.sub.2O.sub.3.
0.2≤x≤0.8  (1)
0.1≤y≤0.65  (2)
3≤m<14  (3)

The magnetic powder for a radio wave absorber is a powder of a hexagonal ferrite having a composition represented by Formula 1, a region B is present on the particle surface of the powder, and Expression 2: 0.3≤content of A atom in region B/content of Al atom in region B≤23.0 and Expression 3: 1.2≤total of content of A atom and content of Al atom in region B/total of content of A atom and content of Al atom in entire powder≤2.5 are satisfied. The region B is a region that is observed as a bright region having a long side diameter of 0.1 μm to 0.6 μm in an image subjected to binarization processing. A represents one or more kinds of atoms (A atom) selected from the group consisting of Sr, Ba, Ca, and Pb, and x satisfies 0.10≤x≤5.00.

AFe.sub.(12-x)Al.sub.xO.sub.19  (Formula 1)

The present invention relates to ferrite particles for bonded magnets and a resin composition for bonded magnets which can provide a bonded magnet molded product capable of realizing a high magnetic force and a complicated multipolar waveform owing to such a feature that the ferrite particles are readily and highly oriented against an external magnetic field in a flowing resin upon injection molding, as well as a bonded magnet molded product obtained by injection-molding the above composition. According to the present invention, there are provided ferrite particles for bonded magnets which have a crystallite size of not less than 500 nm as measured in an oriented state by XRD, and an average particle diameter of not less than 1.30 μm as measured by Fisher method; a resin composition for bonded magnets; and a molded product obtained by injection-molding the composition.