JP2002260908A - Permanent magnet powder, magnet using the same, and method of manufacturing them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ferrite magnet powder that has improved coercive force and restrain its residual magnetic flux density from deteriorating, and to provide a magnet at a low cost. SOLUTION: This magnetic powder contains hexagonal magnet plumbite ferrite as a main phase where Sr is partially substituted with La, and Fe is partially substituted with Mn or a composite of Mn and Co. The composition of the magnetic powder is represented by a formula, (1-x)SrO.(x/2)La2 O3 .(n-y/2-y'/2)Fe2 O3 .yMnO2 .y'CoO, wherein (x), (y), (y') and (n) indicate mol ratios respectively, and (x), (y), (y') and (n) are so set as to satisfy formulas, 0.03<=x<=0.30, 0.01<=y<=0.3, 0<=y'<=0.29, and 6.0<n<=6.5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a ferrite magnet powder, a magnet using the ferrite magnet powder, a method for producing the same, a motor using the magnet powder, and other products using the magnet powder.

[0002]

2. Description of the Related Art Ferrite is a general term for a compound formed from a divalent cation metal oxide and trivalent iron. Ferrite magnets are used for various applications such as motors and generators. As a material of the ferrite magnet, Sr ferrite having a hexagonal structure of magnetoplumbite type (SrFe
₁₂ O ₁₉ ) or Ba ferrite (BaFe ₁₂ O ₁₉ ) is widely used. These ferrites are produced at relatively low cost by powder metallurgy using iron oxide and a carbonate such as strontium (Sr) or barium (Ba) as raw materials.

[0003] The basic composition of the M-type ferrite is usually represented by the chemical formula of "MO · nFe ₂ O _3". The element M is selected from Sr, Ba, Pb, Ni and others.

[0004] Iron ions (Fe ³⁺ ) at each site in ferrite have a spin magnetic moment and are bonded by super-exchange interaction via oxygen ions (O ²⁻ ). At each Fe ³⁺ site, the magnetic moment of Fe ³⁺ is either “up” or “down” along the c-axis. Since there is a difference between the number of sites having an "up" magnetic moment and the number of sites having a "down" magnetic moment, the crystal as a whole exhibits ferromagnetism (ferrimagnetic material).

[0005] Among the magnetic properties of magnetoplumbite ferrite magnets, it is known that the residual magnetic flux density (Br) can be improved by improving the crystal Is and increasing the density of the sintered body and the degree of crystal orientation. I have. on the other hand,
It is known that the coercive force (H _cJ ) can be improved by increasing the abundance of single domain crystals. However, if an attempt is made to increase the density of the sintered body for the purpose of improving the residual magnetic flux density (Br), the coercive force (H _cJ ) will decrease because the crystal growth is promoted. Conversely, if the crystal size is controlled by adding Al ₂ O ₃ or the like to thereby improve the coercive force, the residual magnetic flux density will decrease due to a decrease in the density of the sintered body. In order to improve the magnetic properties of such a ferrite magnet, the composition of the ferrite,
Various studies have been made on additives and manufacturing conditions, but it has been difficult to develop a ferrite magnet in which both the residual magnetic flux density and the coercive force are improved.

Thereafter, Fe is replaced with Zn, and Sr is replaced with La.
A ferrite magnet in which the saturation magnetization (σs) is improved by substituting with a ferrite magnet has been proposed (Japanese Patent Laid-Open No. Hei 9-115715).
And JP-A-10-149910). The ferrite magnet is a ferrimagnetic material in which the magnetic moment of Fe ³⁺ is oriented in the opposite direction depending on the site as described above.
Its saturation magnetization is relatively low.

[0007] However, the above publication discloses that ions having a magnetic moment smaller than that of Fe are referred to as Fe ions.
It is stated that by placing the ion at a particular site, the "downward" magnetic moment can be reduced, thereby increasing the saturation magnetization s. In this publication, L.
Example of using Nd or Pr instead of a, M instead of Zn
An example using n, Co, and Ni is also described.

[0008] Proceedings of the Japan Society of Applied Magnetics (199)
(Distributed on September 20, 2008), the Sr _1-x La _x Co _{x .Fe 12-x} O ₁₉ composition to which La and Co are added provides both coercive force (H _cJ ) and saturation magnetization (σs). An improved ferrite magnet is disclosed.

JP-A-11-307331 discloses La, M
An inexpensive high-performance ferrite magnet is disclosed, which has excellent magnetic properties, particularly BH curve squareness by adding n and Co elements in combination, and is inexpensive.

[0010]

Even with these ferrite magnets, the improvement in both coercive force and saturation magnetization is insufficient. That is, La, Mn, Co
In the composition to which the element is added in combination, the squareness is improved but the magnetization is reduced. In addition, raw materials such as La and Co are expensive, and when used in large amounts, the raw material cost increases. Further, when Zn is added, the magnetization increases, but the coercive force decreases significantly.

The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a ferrite magnet powder in which the residual magnetic flux density is further improved without lowering the coercive force and a magnet using the magnet powder. It is to provide at low cost.

[0012]

This and other objects are achieved by any of the following configurations.

(1) Equation (1-x) SrO · (x / 2)
La ₂ O _3. (Ny−2-y ′ / 2) Fe ₂ O ₃ .yMn
N, x, y, represented by O ₂ · y′CoO and representing a molar ratio
y ′ satisfies the relational expressions of 6.0 <n ≦ 6.5, 0.03 ≦ x ≦ 0.30, 0.01 ≦ y ≦ 0.30, and 0 ≦ y ′ ≦ 0.20, respectively. A magnetic powder mainly composed of a hexagonal magnetoplumbite ferrite phase having the following composition.

(2) The magnetic powder according to the above (1), wherein a relational expression of 0.2 ≦ y / x ≦ 1.0 is satisfied.

(3) The magnetic powder according to the above (1) or (2), wherein the relational expression y> y 'is satisfied.

(4) A bonded magnet containing the magnetic powder according to (1) to (3).

(5) A sintered magnet containing the magnetic powder described in (1) to (3) above.

(6) SrCO_ThreeAnd Fe_TwoO_ThreeRaw material
Oxide powder of La, Mn and Co with respect to powder
Providing a raw material mixed powder to which the powder has been added;
The mixed powder is calcined, whereby (1-x) SrO.
(X / 2) La _TwoO_Three-(Ny / 2-y '/ 2) Fe_Two
O_Three・ YMnO_TwoY′CoO (0.03 ≦ x ≦ 0.3
0, 0.01 ≦ y ≦ 0.30, 0 ≦ y ′ ≦ 0.20,
Hexagonal M-type ferrule having a composition of 6.0 <n ≦ 6.5)
Forming a calcined body of the site and pulverizing the calcined body
And a method for producing a magnetic powder.

(7) The calcination is performed at 1100 ° C. or more and 145
The method for producing a magnetic powder according to the above (6), which is carried out at 0 ° C. or lower.

(8) A method for producing a magnet, comprising: molding and sintering the magnetic powder according to (6).

(9) A method for producing a magnet, comprising: a step of heat-treating the magnetic powder according to (6); and a step of forming the heat-treated magnetic powder into a bonded magnet.

(10) The heat treatment is performed at 700 to 1100.
The method for producing a magnet according to the above (9), wherein the method is performed at a temperature of ° C.

(11) Equation (1-x) SrO. (X /
2) La ₂ O _3. (Ny−2-y ′ / 2) Fe ₂ O ₃ .y
N, x, represented by MnO ₂ · y′CoO, and representing a molar ratio
where y and y ′ are respectively 6.0 <n ≦ 6.5, 0.03 ≦ x ≦ 0.30, 0.01 ≦ y ≦ 0.30, and 0 ≦ y ′ ≦ 0.20. Ferrite magnet having a hexagonal magnetoplumbite-type ferrite phase having a satisfactory composition as a main phase.

(12) Sr, La, Co, Mn, Fe
Sr: 5.4 atomic% or more and 7.4 atomic% or less La: 0.2 atomic% or more and 2.3 atomic% or less Fe: 88.5 atomic% or more and 92.7 atomic% or less Mn: 0.07 atomic% or more and 2.3 atomic% or less Co: hexagonal magnetoplana having a composition of 0 atomic% or more and 1.6 atomic% or less Magnetic powder containing a bite ferrite phase as the main phase.

(13) Sr, La, Co, Mn, Fe
Sr: 5.4 at% or more and 7.4 at% or less La: 0.2 at% or more and 2.3 at% or less Fe: 88 Mn: 0.07 to 2.3 atomic% Co: Hexagonal magnetoplumbite having a composition of 0 to 1.6 atomic% Ferrite magnet whose main phase is a type ferrite phase.

(14) Sr: 5.4 atomic% or more and 7.4 atomic% or less La: 0.2 atomic% or more and 2.3 atomic% with respect to the total amount of metal elements. % Fe or less: 88.5 atomic% or more and 92.7 atomic% or less Mn: 0.07 atomic% or more and 2.3 atomic% or less Co: 0 atomic% or more and 1.6 atomic% or less A method for producing a sintered ferrite magnet having a hexagonal magnetoplumbite-type crystal structure, comprising crushing, drying or concentrating, kneading, shaping in a magnetic field, and sintering a calcined body having a composition.

(15) Equation (1-x) AO · (x / 2)
R ₂ O ₃ · (ny−2) Fe ₂ O ₃ · yMO,
Is at least one element selected from the group consisting of Ba, Sr, Pb, and Ca; R is at least one element selected from the group consisting of Y, Bi, and rare earth elements; Is Mn and / or Co,
N, x, and y representing the molar ratio are each hexagonal having a composition satisfying the relational expression of 6.0 <n ≦ 6.5 0.03 ≦ x ≦ 0.30 0.01 ≦ y ≦ 0.30. A magnetic powder whose main phase is a crystalline magnetoplumbite ferrite phase.

(16) Equation (1-x) AO · (x / 2)
R ₂ O ₃ · (ny−2) Fe ₂ O ₃ · yMO,
Is at least one element selected from the group consisting of Ba, Sr, Pb, and Ca; R is at least one element selected from the group consisting of Y, Bi, and rare earth elements; Is Mn and / or Co,
A compound having a composition in which n, x, and y representing the molar ratio each satisfy a relational expression of 6.0 <n ≦ 6.5 0.03 ≦ x ≦ 0.30 0.01 ≦ y ≦ 0.30. A ferrite magnet whose main phase is a hexagonal magnetoplumbite ferrite phase composed of

(17) Composition formula (1-x) AO. (X /
2) R ₂ O _3. (Ny−2-y ′ / 2) Fe ₂ O ₃ .yM
A is represented by O, A is at least one element selected from the group consisting of Ba, Sr, Pb, and Ca;
At least one element selected from the group consisting of Y, Bi, and a rare earth element, wherein M is Mn and / or Co, and 6.0 <n ≦ 6.5 0.03 ≦ x ≦ 0 .30 0.01 ≦ y ≦ 0.30 Substantially hexagonal magnetoplumbite characterized in that a calcined body having a basic composition satisfying 0.01 ≦ y ≦ 0.30 is pulverized, dried or concentrated, kneaded, molded in a magnetic field, and sintered. A method for producing a sintered ferrite magnet having a type crystal structure.

(18) The above (4), (5), (1)
A rotating machine including the magnet according to 1), (13), or (16).

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Conventionally, when the n value of ferrite (MO.nFe ₂ O ₃ ) having a magnetoplumbite type crystal structure is larger than 6.0, the Fe
It has been known that the solid-phase reaction between ₂ O ₃ and SrCO ₃ becomes insufficient, and unreacted Fe ₂ O ₃ remains, thereby deteriorating the magnetic properties.

The present inventor has replaced a part of Sr with La,
It has been found that the following phenomenon occurs when a part of Fe is replaced by Mn, and the present invention has been reached.

(1) The crystal grain size of the calcined body is reduced. The size of normal ferrite crystal particles is 1 to 10 μm
However, when La and Mn are added, about 1
μm.

(2) When the value of n is larger than 6.0, the magnetic properties of the magnet are maximized.

(3) When the ratio represented by the added amount of Mn / the added amount of La is in the range of 0.2 to 1.0, the residual magnetic flux density Br hardly decreases, and the coercive force H _cJ is reduced. To increase.

(4) Even when a calcined body is prepared by adding Co, the crystal particle diameter of the calcined body becomes small and the calcined body becomes dense. Even in this case, the magnetic properties of the magnet are maximized when the n value is greater than 6.0.

In general, in the magnetoplumbite type ferrite, unreacted hematite (α-Fe ₂ O ₃ ) remains when the n value exceeds 6.0, regardless of the presence or absence of La, and the crystal grain size is reduced. Become smaller. Hematite usually reduces magnetic properties.

When Mn is added to such ferrite, the reaction at the time of calcination tends to proceed. Therefore, if Mn is added at the same time as La, even if the n value exceeds 6.0, the crystal particle diameter does not increase and almost no heterophase is generated. This is presumed to be due to the fact that hematite is uniformly dissolved in the calcined body.

In the case of the present invention, another reason for obtaining good magnetic properties under the condition of n> 6.0 is that Mn and Co react with excess hematite during the solid-phase reaction, It is also presumed that a spinel phase or a W-type phase was formed.

In the present invention, the magnetoplumbite type ferrule is used.
Sr in light²⁺Part of La ³⁺With Fe³⁺
Part of Mn²⁺Or Mn⁴⁺And Co²⁺Replace with compound of
Then, the difference in valence is compensated. About replacement amount
Indicates that the relation of x = y or x = y + y ′ is almost established.
Preferably, x = y or x = y + y ′
Does not need to be strictly established. In the present invention, x>
It is preferable that the relationship of y, x> y + y 'holds.
No. The ratio of y / x is 0.2 or more and 1.0 or less.
It is preferably within the range.

When a part of Fe is substituted with a complex of Mn ⁴⁺ and Co ²⁺ , it is preferable that the relation y> y ′ is satisfied. When this relationship is established, the cost of raw materials can be reduced, so that a ferrite magnet can be provided at low cost.

The amount of La added is preferably 0.03 mol or more and 0.30 mol or less. A more preferable range of the added amount of La is 0.05 to 0.25 mol. If the amount of La is less than the above range, the effect of the addition is small, and if the amount of La is more than the above range, an orthoferrite phase and other phases are generated in addition to the M phase, so that the magnetic properties deteriorate. Part of La is converted to Ce, Pr, Nd, Sm, Eu, Gd having an ionic radius close to that of Sr ^2+.
May be substituted.

Mn is a transition metal like Fe, and has a similar ionic radius. For this reason, it is considered that Mn replaces a part of Fe. Mn magnetic moment of ²⁺ are the same as Fe ³⁺ (the magnetic moment of the Mn ^2+: 5, Fe ³⁺ magnetic moments: 5) because it is, by substituting a part of Fe in Mn, the remanence It is considered that Br hardly decreases and the coercive force H _cJ increases. The preferred range of the added amount of Mn is 0.01 mol or more and 0.30 mol or less, and the more preferred range is 0.03 mol or more and 0.15 mol or less.

According to experiments, the preferable range of the ratio of the added amount of Mn / the added amount of La is 0.2 to 1.0, and the more preferable range is 0.5 to 0.8.

In order to improve the magnetic characteristics, Co is used as the element M.
Ni, Cu, and / or Zn may be added at about 1% by weight in addition to and Mn.

Since Co has a larger magnetocrystalline anisotropy than other transition metals, the addition of Co increases the coercive force. A preferable range of the amount of Co to be added is 0 to 0.20 mol. If the amount of Co exceeds 0.20 mol, the coercive force decreases.

The n value is preferably larger than 6.0 and equal to or smaller than 6.5, more preferably larger than 6.0 and equal to or smaller than 6.2.

It is preferable that hematite does not exist in the calcined body, but hematite may partially exist. It is preferable to add an additive that reduces hematite or an additive that improves magnetic properties. Such additives include, for example, boric acid, compounds containing boron,
Bi ₂ O ₃ , Bi-containing compounds, chlorides (NaCl, Mg
Cl, KCl, SrCl ₂ , BaCl ₂ ) and hematite to form a compound having an M phase, a spinel phase, and a W phase.

If necessary, B ₂ O ₃ ,
Another compound containing H ₃ BO ₃ or the like may be added at about 1% by weight. The preferred average particle size of the iron oxide raw material is 0.5 μm to
1.0 μm.

Next, a method for manufacturing a ferrite magnet of the present invention will be described.

First, a powder of SrCO _{3 and} a powder of Fe ₂ O ₃ are mixed at a molar ratio in the range of 1: 6.0 to 1: 6.5. At this time, La ₂ O ₃ , Mn ₃ O ₄ , Co ₃ O _{4 and the} like are added to the raw material powder. La, Mn, and Co are preferably added as respective oxide powders, but powders other than oxides (eg, carbonate, hydroxide,
Nitrate, chloride, etc.) and in solution.

The mixing of the raw material powders may be either wet or dry. Stirring the raw material powder with a medium such as a steel ball enables more uniform mixing. In the case of a wet method, water is used as a solvent. Known dispersants such as ammonium polycarboxylate and calcium gluconate may be used for the purpose of dispersing the raw material powder. The mixed raw material slurry is dehydrated to be a mixed raw material powder.

Next, the mixed raw material powder is heated to a temperature of 1100 ° C. to 1450 ° C. using an electric furnace, a gas furnace or the like, and a magnetoplumbite type ferrite compound is formed by a solid phase reaction. This process is called "calcination", and the obtained compound is called "calcined body". Calcination time is 0.5-5
It is preferably time. Temperature range from 1200 to 13
50 ° C. is more preferred.

In the calcination step, a ferrite phase is formed by a solid-phase reaction with an increase in temperature, and the ferrite phase is completed at about 1100 ° C. At a temperature lower than this temperature, unreacted hematite (iron oxide) remains and magnet properties are reduced. Is low. When the temperature exceeds 1100 ° C., the effects of the present invention occur. On the other hand, the calcination temperature is 145
If the temperature exceeds 0 ° C., crystal grains may grow too much, which may cause inconveniences such as requiring a long time for pulverization in the pulverization step.

From the above, it is preferable that the calcining temperature is set within a temperature range of more than 1100 ° C. and 1400 ° C. or less.

The calcined body obtained by this calcining step is
Has a main phase of magnetoplumbite ferrite represented by the following formula, the average particle diameter, 0.1 to 1
It is in the range of 0 μm.

(1-x) SrO. (X / 2) La ₂ O _3. (Ny−2-y ′ / 2) Fe ₂ O ₃ .yMnO ₂ .y′CoO (Chemical Formula) where 0 0.03 ≦ x ≦ 0.30, 0.01 ≦ y ≦ 0.
30, 0 ≦ y ′ ≦ 0.20 and 6.0 <n ≦ 6.5 are satisfied.

By pulverizing and / or pulverizing such a calcined body, the magnetic powder of the present invention can be obtained. The production of the calcined body may be performed using other known production techniques such as a spray pyrolysis method and a coprecipitation method.

Next, with respect to the calcined body, CaO, Si
O ₂ , Cr ₂ O ₃ and Al ₂ O ₃ (CaO: 0.3% by weight
1.5 wt% or less, SiO _2: 0.2 wt% to 1.0 wt% or less, Cr ₂ O _3: 0 wt% to 5.0 wt% or less, Al ₂ O _3: 0 wt% or more 5 0.0% by weight or less) to prepare a calcined mixture.

The calcined mixture is pulverized into fine particles by a fine pulverizing step using a vibration mill, a ball mill and / or an attritor. The average particle diameter of the fine particles is preferably about 0.4 to 0.8 μm (air permeation method). The fine pulverization step is preferably performed by combining dry pulverization and wet pulverization. In wet grinding, aqueous solvents such as water and various non-aqueous solvents (for example, acetone,
Organic solvents such as ethanol and xylene). During wet grinding, a slurry in which the solvent and the calcined powder are mixed is generated. The slurry contains various known dispersants and surfactants in a solid content ratio of 0.2% by weight or more.
It is preferable to add 0% by weight or less. Dehydration and drying may be performed after wet pulverization. In the pulverization step, other compounds including Bi ₂ O _{3 and the} like may be added in an amount of about 1% by weight or less.

Thereafter, press molding is performed in a magnetic field or in a non-magnetic field while removing the solvent in the slurry. During molding,
The crystal orientation of the powder particles may be aligned by applying a magnetic field (referred to as orientation). This operation can dramatically improve the magnetic force. In order to further improve the orientation, a dispersant and a lubricant may be added in an amount of 0.01% by weight or more and 1.0% by weight or less.

After press molding, a degreasing step, a sintering step,
Through known manufacturing processes such as a processing step, a cleaning step, and an inspection step, a ferrite magnet product is finally completed.
The sintering step is performed in air at, for example, 1150 ° C. to 1250 ° C.
May be performed in the temperature range of 0.5 to 2 hours. The oxygen concentration in the air during sintering must be at least 8% or more. If the oxygen concentration is less than 8%, the powder particles fuse together at the time of sintering, abnormally coarsening, and the magnetic properties, particularly the coercive force, decrease. The average particle size of the sintered magnet obtained in the sintering step is, for example, 0.5 to 2 μm.

In addition to the above raw material powders, if necessary, other compounds such as Si, Ca, Pb, Al, Ga, Cr,
Sn, In, Co, Ni, Ti, Mn, Cu, Ge,
A compound containing V, Nb, Zr, Li, Mo, Bi, a rare earth element (including Y) and the like may be added in an amount of about 3% by weight or less. Further, impurities such as unavoidable components may be contained in a small amount.

It is to be noted that the above-mentioned ferrite magnetic powder may be mixed with a flexible rubber, a hard and light plastic, or the like to form a bonded magnet. In this case, after the magnetic powder of the present invention is mixed with a binder and an additive, molding is performed. The molding process is performed by a method such as injection molding, extrusion molding, and roll molding. Also,
When used as the above-mentioned bonded magnet, heat treatment of the ferrite magnetic powder is performed at a temperature of 700 to 1100 ° C. in a temperature range of 0.1 to 3 ° C.
It should be done in time. Temperature range of heat treatment is 900 ~
1000 ° C. is more preferred.

The heat treatment is performed to remove crystal strain introduced into the calcined particles during the step of pulverizing the calcined body.
By the heat treatment at 700 ° C. or higher, the crystal strain in the calcined particles is relaxed and the coercive force is restored. However, in the heat treatment at 1100 ° C. or more, the coercive force decreases because the powder starts to grow. On the other hand, the magnetization increases with the coercive force up to 1000 ° C., but above this temperature, the degree of orientation decreases,
Magnetization decreases. It is considered that the reason for this is that fusion of the powder particles occurs. From the above, it is preferable that the heat treatment be performed in a temperature range of 700 ° C. to 1100 ° C. for 1 second to 3 hours. A more preferable range of the heat treatment temperature is 900 ° C. or more and 1000 ° C. or less.

After the ferrite magnetic powder is subjected to a heat treatment, it is kneaded with various known binders and applied, whereby a coating type magnetic recording medium can be manufactured.

Further, a thin film magnetic layer used for a magnetic recording medium can be formed by a sputtering method using the ferrite magnet of the present invention as a target. Also,
Instead of a ferrite magnet, an oxide of each element may be used as a target. By performing a heat treatment on the thin film formed by the sputtering method, a thin film magnetic layer using the ferrite magnet of the present invention can be manufactured.

The rotating machine of the present invention is characterized in that it has a ferrite magnet manufactured by the above method, and its specific structure itself may be the same as a known rotating machine. .

In place of Sr, Ba, Ca and P
At least one element selected from b may be used. Further, instead of La, together with La, a part of Sr may be substituted with at least one element selected from rare earth elements including Y and Bi.

In consideration of the above, the composition of the ferrite is (1-x) AO. (X / 2) R ₂ O _3. (N
-Y / 2) represented by Fe ₂ O ₃ · yMO. Where A
Is at least one element selected from the group consisting of Ba, Sr, Pb, and Ca; R is at least one element selected from the group consisting of Y, Bi, and rare earth elements; Is Mn and / or Co,
N, x, and y representing the molar ratio are respectively 6.0 <n ≦
6.5, 0.03 ≦ x ≦ 0.30, and 0.01 ≦ y
Satisfies ≦ 0.30.

The ferrite of the present invention comprises Sr, La, C
Sr containing o, Mn, and Fe, and the composition ratio of each metal element is 5.4 atomic% or more and 7.4 atomic% or less, and 0.2 atomic% or more and 2.3 atomic% or less with respect to the total metal element amount. La, 8
Fe of not less than 8.5 atomic% and not more than 92.7 atomic%, 0.07
Mn of at least 2.3 atomic% and at least 0 atomic%.
Contains 6 atomic% or less of Co.

[0072]

(Embodiment 1) First, (1-x) SrO. (X
_{/ 2) La 2 O 3 ·} (n-y / 2-y '/ 2) Fe 2 O 3 ·
In the composition formula of yMnO ₂ · y′CoO, n = 5.8
６6.7, x = 0.20, y = 0.15, and y ′ =
0, and n = 5.8-6.
7, x = 0.20, y = 0.15, and y ′ = 0.0
5 and the raw material powder blended to be 5
Calcination was performed at 300 ° C. for about 2 hours. The calcined body thus obtained was coarsely pulverized by a sample mill so that the particle size became about 3 μm or less, to prepare a magnetic powder.

Next, the above-mentioned magnetic powder is further added to 0.5 to 0.5.
After pulverizing to a size of 7 μm, CaCO ₃ and SiO ₂ were added to the obtained pulverized powder and mixed.
The amount of CaCO ₃ added was 0.6% by weight, and the amount of SiO ₂ was 0.45% by weight. The finely pulverized powder thus obtained was molded in a magnetic field, and then sintered at 1200 ° C. for 30 minutes to produce a sintered magnet. The magnetic properties of the sintered magnet were measured. The result is shown in FIG.

As can be seen from FIG. 1, the sintered magnet is
By substituting a part of Fe with Mn or Mn and Co, the conventional n = 5.8, 5.9, or 6.0 in the range where the n value is greater than 6.0 and 6.5 or less. Magnetic properties superior to those of the sintered magnets. Also, Mn and C
The coercive force (H _cJ ) was improved in the case where Fe was replaced by _combining o with that in the case where Fe was replaced with only Mn.

Example 2 First, (1-x) SrO.
_{(X / 2) La 2 O} 3 · (n-y / 2-y '/ 2) Fe 2
In O ₃ .yMnO ₂ .y'CoO, n = 6.1, x
= 0.20, y = 0 to 0.4, and y '= 0. Next, a sintered body was produced in the same manner as in Example 1, and its magnetic properties were measured. The result is shown in FIG.

As can be seen from FIG. 2, the magnetic characteristics of this sintered body are such that y = y ≦ 0.05 ≦ y ≦ 0.20.
0 showed better magnetic properties than the comparative example. Also, y /
It was also found that when x> 1.0, the magnetic properties were degraded. When x is 0.3 or less, the present embodiment (x =
0.20).

Example 3 First, (1-x) SrO.
_{(X / 2) La 2 O} 3 · (n-y / 2-y '/ 2) Fe 2
In O ₃ .yMnO ₂ .y′CoO, raw materials were blended so that each composition ratio became a value shown in Table 1 below.

Next, to produce a sintered body in the same manner as in Example 1, to measure the magnetic properties. Table 1 shows the results.

[0079]

[Table 1]

[0080] Here, B _r is the residual magnetic flux density, H _cJ coercive force, (BH) _max is the maximum magnetic energy product.

In this sintered body, when the amount x of La added was in the range of 0.05 or more and 0.30 or less, magnetic properties superior to those of the comparative example were obtained.

(Embodiment 4) First, (1-x) SrO.
_{(X / 2) La 2 O} 3 · (n-y / 2-y '/ 2) Fe 2
In O ₃ .yMnO ₂ .y'CoO, n = 6.1, x
= 0.20, y = 0.10, and y '= 0 to 0.30. Next, a sintered body was produced in the same manner as in Example 1, and its magnetic properties were measured. The result is shown in FIG.

As can be seen from FIG. 3, the magnetic properties of this sintered body are such that the y value indicating the amount of Co added is 0.05 or more and 0.10 or more.
In the range, the magnetic properties were superior to those of the conventional sintered body with y = 0. When the relationship of y / x> 1.0 was satisfied, the magnetic properties were reduced. Note that x is 0.03
In this embodiment (x = 0.2
The same result as in the case of (0) was obtained.

(Example 5) In the same manner as in the above method, a C-shaped sintered magnet for a motor was prepared, and this was replaced with a sintered magnet of a conventional material, incorporated in a motor, and operated under rated conditions. As a result, good characteristics were obtained. When the torque was measured, the torque was higher than that of a motor using a conventional sintered magnet made of a material.

[0085]

According to the present invention, it is possible to improve the coercive force while suppressing a decrease in the residual magnetic flux density of the magnet, and it is possible to manufacture and provide a magnet having excellent magnetic properties at low cost.

[Brief description of the drawings]

FIG. 1 (1-x) SrO. (X / 2) La ₂ O _3. (N
-Y / 2-y '/ 2 ) Fe 2 O 3 · yMnO 2 · y'Co
In a ferrite sintered magnet having a composition of O, x =
0.20, y = 0.15, which is a graph showing the n value dependent remanence B _r and coercivity H _cJ in the case of a y '= 0,0.05.

FIG. 2 shows the relationship between (1-x) SrO. (X / 2) La ₂ O _3. (N
-Y / 2-y '/ 2 ) Fe 2 O 3 · yMnO 2 · y'Co
In a sintered ferrite magnet having a composition of O, n =
6.1, x = 0.20, which is a graph showing the y values dependent remanence B _r and coercivity H _cJ in the case of a y '= 0.

FIG. 3 (1-x) SrO. (X / 2) La ₂ O _3. (N
-Y / 2-y '/ 2 ) Fe 2 O 3 · yMnO 2 · y'Co
In a sintered ferrite magnet having a composition of O, n =
6.1, x = 0.20, which is a graph showing the y 'values dependent remanence B _r and coercivity H _cJ in the case of a y = 0.10.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Etsushi Oda 2-15-17 Egawa, Shimamoto-cho, Mishima-gun, Osaka Prefecture F-term in Sumitomo Special Metals Co., Ltd. Yamazaki Works (reference) 4G002 AA06 AA08 AA09 AA10 AB01 AE04 5E040 AB04 BB03 BD01 CA01 HB01 HB03 HB05 HB06 HB11 HB17 NN02 NN18 5E062 CD01 CD02 CE01 CG02

Claims (18)

[Claims] 1. The formula (1-x) SrO · (x / 2) La ₂
O _3. (Ny−2-y ′ / 2) Fe ₂ O ₃ .yMnO _2.
The molar ratio of n, x, y, and y ′ represented by y′CoO is 6.0 <n ≦ 6.5, 0.03 ≦ x ≦ 0.30, 0.01 ≦ y ≦ 0, respectively. A magnetic powder mainly composed of a hexagonal magnetoplumbite-type ferrite phase having a composition satisfying a relational expression of 0.30 and 0 ≦ y ′ ≦ 0.20. 2. The magnetic powder according to claim 1, which satisfies a relational expression of 0.2 ≦ y / x ≦ 1.0. 3. The magnetic powder according to claim 1, which satisfies a relational expression of y> y ′. 4. A bonded magnet comprising the magnetic powder according to claim 1. 5. A sintered magnet comprising the magnetic powder according to claim 1. 6. SrCO_ThreeAnd Fe_TwoO_ThreeRaw material powder
On the other hand, each oxide powder of La, Mn and Co was added.
Preparing the added raw material mixed powder; and calcining the raw material mixed powder, thereby (1-x) S
rO · (x / 2) La _TwoO_Three-(Ny / 2-y '/ 2)
Fe_TwoO_Three・ YMnO_TwoY'CoO (0.03 ≦ x ≦
0.30, 0.01 ≦ y ≦ 0.30, 0 ≦ y ′ ≦ 0.2
0, 6.0 <n ≦ 6.5)
Forming a calcined body of ferrite, and pulverizing the calcined body.
Construction method. 7. The method according to claim 6, wherein the calcination is performed at a temperature of 1100 ° C. or more and 1450 ° C. or less. 8. A method for producing a magnet, comprising: molding and sintering the magnetic powder according to claim 6. 9. A method for producing a magnet, comprising: a step of heat-treating the magnetic powder according to claim 6; and a step of forming the heat-treated magnetic powder into a bonded magnet. 10. The method according to claim 9, wherein the heat treatment is performed at a temperature of 700 to 1100 ° C. 11. The formula (1-x) SrO · (x / 2) La
₂ O _3. (Ny−2-y ′ / 2) Fe ₂ O ₃ .yMnO ₂
N, x, y, y ′ represented by y′CoO and representing a molar ratio
Have compositions satisfying the relational expressions of 6.0 <n ≦ 6.5, 0.03 ≦ x ≦ 0.30, 0.01 ≦ y ≦ 0.30, and 0 ≦ y ′ ≦ 0.20, respectively. A ferrite magnet whose main phase is a hexagonal magnetoplumbite ferrite phase. 12. A composition containing Sr, La, Co, Mn and Fe, wherein the composition ratio of each metal element is at least 5.4 atomic% and not more than 7.4 atomic% with respect to the total amount of metal elements. La: 0 0.2 atomic% or more and 2.3 atomic% or less Fe: 88.5 atomic% or more and 92.7 atomic% or less Mn: 0.07 atomic% or more and 2.3 atomic% or less Co: 0 atomic% or more, 1 A magnetic powder mainly composed of a hexagonal magnetoplumbite ferrite phase having a composition of not more than 0.6 atomic%. 13. An alloy containing Sr, La, Co, Mn, and Fe, and has a composition ratio of Sr: 5.4 atomic% or more and 7.4 atomic% or less to the total amount of each metal element. 2 atomic% or more and 2.3 atomic% or less Fe: 88.5 atomic% or more and 92.7 atomic% or less Mn: 0.07 atomic% or more and 2.3 atomic% or less Co: 0 atomic% or more, A ferrite magnet mainly composed of a hexagonal magnetoplumbite ferrite phase having a composition of 6 atomic% or less. 14. The composition ratio of each metal element is Sr: 5.4 atomic% or more and 7.4 atomic% or less La: 0.2 atomic% or more and 2.3 atomic% with respect to the total amount of metal elements. Fe: 88.5 atomic% or more and 92.7 atomic% or less Mn: 0.07 atomic% or more and 2.3 atomic% or less Co: Basic composition represented by 0 atomic% or more and 1.6 atomic% or less A method for producing a sintered ferrite magnet having a hexagonal magnetoplumbite-type crystal structure, comprising crushing, drying or concentrating, kneading, shaping in a magnetic field, and sintering a calcined body having the above. 15. The formula (1-x) AO · (x / 2) R_TwoO_Three
・ (Ny / 2) Fe _TwoO_ThreeA is selected from the group consisting of Ba, Sr, Pb and Ca
R is selected from the group consisting of Y, Bi, and rare earth elements
M is Mn and / or Co, and n, x, and y representing a molar ratio are respectively 6.0 <n ≦ 6.5 0.03 ≦ x ≦ 0.30 0.01 ≦ y ≦ 0.30 Hexagonal Magnetoplan having a Composition Satisfying the Relational Expression: 0.01 ≦ y ≦ 0.30
Magnetic powder containing a bite ferrite phase as the main phase. 16. The formula (1-x) AO. (X / 2) R_TwoO_Three
・ (Ny / 2) Fe _TwoO_ThreeA is selected from the group consisting of Ba, Sr, Pb and Ca
R is selected from the group consisting of Y, Bi, and rare earth elements
M is Mn and / or Co, and n, x, and y representing a molar ratio are respectively 6.0 <n ≦ 6.5 0.03 ≦ x ≦ 0.30 0.01 ≦ y ≦ 0.30 Consists of a compound having a composition satisfying the relational expression:
Main phase is hexagonal magnetoplumbite-type ferrite phase
Ferrite magnet. 17. Composition formula (1-x) AO. (X / 2) R
Is represented by _{2 O 3 · (n-y} / 2-y '/ 2) Fe 2 O 3 · yMO, A is, Ba, Sr, Pb, is at least one element selected from the group consisting of Ca R is at least one element selected from the group consisting of Y, Bi, and a rare earth element, M is Mn and / or Co, and 6.0 <n ≦ 6.5 0.03 ≦ x ≦ 0.30 Substantially hexagonal, characterized by crushing, drying or concentrating, kneading, shaping in a magnetic field, and sintering a calcined body having a basic composition satisfying 0.01 ≦ y ≦ 0.30. For producing a sintered ferrite magnet having a monocrystalline magnetoplumbite crystal structure. 18. The method according to claim 4, 5, 11, 13, or 1.
A rotating machine comprising the magnet according to 6.