Magnetic powder, manufacturing method of magnetic powder and bonded magnets

Magnetic powder composed of an alloy composition represented by Rx(Fe1−aCoa)100−x−y−zByMz (where R is at least one kind of rare-earth element excepting Dy, M is at least one kind of element selected from Ti, Cr, Nb, V, Mo, Hf, W, Mn, Zr and Dy, x is 7.1-9.9 at %, y is 4.6-8.0 at %, z is 0.1-3.0 at %, and a is 0-0.30), and the magnetic powder being constituted from a composite structure having a soft magnetic phase and a hard magnetic phase,

• wherein when the magnetic powder is mixed with a binding resin and then the mixture is subjected to injection molding or extrusion molding to form a bonded magnet having a density ρ[Mg/m3], a remanent magnetic flux density Br[T] of the bonded magnet at room temperature satisfies a relationship represented by a formula of Br/ρ[×10−6T·m3/g]≧0.125 and an intrinsic coercive force HCJ of the bonded magnet at room temperature is in a range of 400-760 kA/m.

A method of manufacturing magnetic powder, in which a melt spun ribbon is obtained by colliding a molten alloy of a magnetic material onto a circumferential surface of a cooling roll which is rotating to cool and then solidify it, and then thus obtained melt spun ribbon is milled to obtain the magnetic powder, in which the magnetic powder is composed of an alloy composition represented by Rx(Fe1−aCoa)100−x−y−zByMz (where R is at least one kind of rare-earth element excepting Dy, M is at least one kind of element selected from Ti, Cr, Nb, V, Mo, Hf, W, Mn, Zr and Dy, x is 7.1-9.9 at %, y is 4.6-8.0 at %, z is 0.1-3.0 at %, and a is 0-0.30), and the magnetic powder being constituted from a composite structure having a soft magnetic phase and a hard magnetic phase, wherein when the magnetic powder is mixed with a binding resin and then the mixture is subjected to injection molding or extrusion molding to form a bonded magnet having a density ρ[Mg/m3], a maximum magnetic energy product (BH)max[kJ/m3] of the bonded magnet at room temperature satisfies a relationship represented by a formula of (BH)max/ρ2[×10−9J·m3/g2]≧2.10, and an intrinsic coercive force HCJ of the bonded magnet at room temperature is in a range of 400-760 kA/m.

A method of manufacturing magnetic powder, in which a melt spun ribbon is obtained by colliding a molten alloy of a magnetic material onto a circumferential surface of a cooling roll which is rotating to cool and then solidify it, and then thus obtained melt spun ribbon is milled to obtain the magnetic powder, in which the magnetic powder being composed of an alloy composition represented by Rx(Fe1−aCoa)100−x−y−zByMz (where R is at least one kind of rare-earth element excepting Dy, M is at least one kind of element selected from Ti, Cr, Nb, V, Mo, Hf, W, Mn, Zr and Dy, x is 7.1-9.9 at %, y is 4.6-8.0 at %, z is 0.1-3.0 at %, and a is 0-0.30), and the magnetic powder being constituted from a composite structure having a soft magnetic phase and a hard magnetic phase, wherein when the magnetic powder is mixed with a binding resin and then the mixture is subjected to injection molding or extrusion molding to form a bonded magnet having a density ρ[Mg/m3], a remanent magnetic flux density Br[T] of the bonded magnet at room temperature satisfies a relationship represented by a formula of Br/ρ[×10−6T·m3/g]≧0.125, and an intrinsic coercive force HCJ of the bonded magnet at room temperature is in a range of 400-760 kA/m.

A bonded magnet manufactured by mixing magnetic powder with a binding resin and then subjecting the mixture to injection molding or extrusion molding, in which the magnetic powder is composed of an R—TM—B based alloy having at least one element selected from Ti, Cr, Nb, V, Mo, Hf, W, Mn, Zr and Dy (where R is at least one kind of rare-earth element excepting Dy, and TM is a transition metal mainly containing Fe), the bonded magnet being characterized in that when a density of the bonded magnet is ρ[Mg/m3], a maximum magnetic energy product (BH)max[kJ/m3] of the bonded magnet at room temperature satisfies a relationship represented by a formula of (BH)max/ρ2[×10−9J·m3/g2]≧2.10, and an intrinsic coercive force HCJ of the bonded magnet at room temperature is in a range of 400-760 kA/m.

A bonded magnet manufactured by mixing magnetic powder with a binding resin, and then subjecting the mixture to injection molding or extrusion molding, wherein the magnetic powder being composed of an R—TM—B based alloy having at least one element selected from Ti, Cr, Nb, V, Mo, Hf, W, Mn, Zr and Dy (where R is at least one kind of rare-earth element excepting Dy, and TM is a transition metal mainly containing Fe), the bonded magnet being characterized in that when a density of the bonded magnet is ρ[Mg/m3], a remanent magnetic flux density Br[T] of the bonded magnet at room temperature satisfies a relationship represented by a formula of Br/ρ[×10−6T·m3/g]≧0.125, and an intrinsic coercive force HCJ of the bonded magnet at room temperature is in a range of 400-760 kA/m.

The magnetic powder as claimed in claim 24, wherein a thickness of the melt spun ribbon is 10-40 μm.