Ferrite magnet and method for producing same
AssigneeHitachi Metals, Ltd.
InventorsTakashi Takami, Yutaka Kubota, Yasunobu Ogata
Life of this patent
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Abstract
The ferrite magnet having a composition represented by the general formula: (A.sub.1-x R.sub.x)O.multidot.n(Fe.sub.1-y M.sub.y).sub.2 O.sub.3 ! (by atomic ratio), wherein A is Sr and/or Ba, R is at least one element selected from the group consisting of La, Nd, Pr, Sm, Eu and Gd, La being indispensable, M is at least one element selected from the group consisting of Mn, Co and Ni, and x, y and n meet 0.05.ltoreq.x.ltoreq.0.5, x/(2.4n).ltoreq.y.ltoreq.x/(1.6n) and 5.4.ltoreq.n.ltoreq.6.0, respectively is produced by preparing a starting material powder having the above composition and an average particle size of 0.4-0.7 .mu.m, and subjecting the starting material powder to molding in a magnetic field and then to sintering.
Claims10
A ferrite magnet having a composition represented by the general formula (1):
- (A.sub.1-x R.sub.x)O.multidot.n(Fe.sub.1-y M.sub.y).sub.2 O.sub.3 !(1),
- wherein A is Sr and/or Ba, R is at least one element selected from the group consisting of La, Nd, Pr, Sm, Eu and Gd, La being indispensable, M is at least one element selected from the group consisting of Mn, Co and Ni, and x, y and n meet 0.05.ltoreq.x.ltoreq.0.5, x/(2.4n).ltoreq.y.ltoreq.x/(1.6n) and 5.4.ltoreq.n.ltoreq.6.0, respectively.
A ferrite magnet having a composition represented by the general formula (2):
- (A.sub.1-x R.sub.x)O.multidot.nFe.sub.1-y-z M.sub.y Zn.sub.z).sub.2 O.sub.3 ! (2),
- wherein A is Sr and/or Ba, R is at least one element selected from the group consisting of La, Nd, Pr, Sm, Eu and Gd, La being indispensable, M is at least one element selected from the group consisting of Mn, Co and Ni, Co being indispensable, and x, y, z and n meet 0.05.ltoreq.x.ltoreq.0.5, x/(2.4n).ltoreq.(y+z).ltoreq.x/(1.6n) and 5.4.ltoreq.n.ltoreq.6.0, respectively,
- wherein Zn is indispensable in the composition represented by the general formula (2), and
- wherein the content of Co based on a total amount of M and Zn is at least 50 atomic percent.
A method for producing a ferrite magnet having a composition represented by the general formula (1):
- (A.sub.1-x R.sub.x)O.multidot.n(Fe.sub.1-y M.sub.y).sub.2 O.sub.3 !(1),
- wherein A is Sr and/or Ba, R is at least one element selected from the group consisting of La, Nd, Pr, Sm, Eu and Gd, La being indispensable, M is at least one element selected from the group consisting of Mn, Co and Ni, and x, y and n meet 0.05.ltoreq.x.ltoreq.0.5, x/(2.4n).ltoreq.y.ltoreq.x/(1.6n) and 5.4.ltoreq.n.ltoreq.6.0, respectively, comprising the steps of preparing a starting material powder having said composition and an average particle size of 0.4-0.7 .mu.m, and subjecting said starting material powder to molding in a magnetic field and then to sintering.
A method for producing a ferrite magnet having a composition represented by the general formula (2):
- (A.sub.1-x R.sub.x)O.multidot.nFe.sub.1-y-z M.sub.y Zn.sub.z).sub.2 O.sub.3 ! (2),
- wherein A is Sr and/or Ba, R is at least one element selected from the group consisting of La, Nd, Pr, Sm, Eu and Gd, La being indispensable, M is at least one element selected from the group consisting of Mn, Co and Ni, Co being indispensable, and x, y, z and n meet 0.05.ltoreq.x.ltoreq.0.5, x/(2.4n).ltoreq.(y+z).ltoreq.x/(1.6n) and 5.4.ltoreq.n.ltoreq.6.0, respectively, wherein Zn is indispensable in the composition represented by the general formula (2), and wherein the content of Co based on a total amount of M and Zn is at least 50 atomic percent;
- comprising the steps of
- preparing a starting material powder having said composition and an average particle size of 0.4-0.7 .mu.m;
- and
- subjecting said starting material powder to molding in a magnetic field and then to sintering.
Dependencies are inferred from the claim text.