JP2002118012A - Ferrite magnet, rotary machine and magnet roll using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-performance ferrite magnet, which has higher coercive force iHc (or a higher coercive force iHc and a higher residual magnetic flux density Br) than the conventional ferrite magnet has and a substantial magnetoplumbite type crystal structure having a high aspect ratio. SOLUTION: This ferrite magnet has a basic composition expressed by the general formula of (A1-xRx)O.n[(Fe1-yMy)2O3] (atomic ratio) (wherein, A, R, and M respectively denote Sr and/or Ba, at least one kind of rare-earth element including Y, and at least one kind of element selected from among a group composed of Co, Mn, Ni, and Zn and (x), (y), and (n) respectively satisf the relations of 0.01<=x<=0.4, 0.005<=y<=0.04, and 5<=n<=6) and the magnetoplumbite type crystal structure. In the magnet, in addition, the concentrations of the R and/or M elements in the boundaries of magnetoplumbite crystal grains are higher than those of the elements in the crystal grains.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnet having a substantially magnetoplumbite type crystal structure which is extremely useful in a wide range of magnet application fields, for example, a rotating machine for automobiles or electric equipment, a magnet roll for copying machines, and the like. A high performance ferrite magnet having a higher coercive force iHc (or higher coercive force iHc and residual magnetic flux density Br) than conventional ferrite magnets, and having a high squareness ratio (Hk / iHc) as desired. The present invention relates to a high-performance ferrite magnet having a structure, a rotating machine and a magnet roll using the same.

[0002]

2. Description of the Related Art Ferrite magnets have been used in various applications including rotating machines such as motors and generators. In recent years, ferrite magnets having higher magnetic properties have been demanded especially for the purpose of reducing the size and weight in the field of rotating machines for automobiles and for the purpose of increasing the efficiency in the field of rotating machines for electric equipment.

Conventionally, high-performance sintered magnets such as Sr ferrite or Ba ferrite have been manufactured through the following steps, for example. First, after mixing iron oxide and a carbonate of Sr or Ba, a ferrite reaction is caused by calcination to produce a calcined clinker. Next, the calcined clinker is coarsely pulverized,
In addition, SiO ₂ , SrCO ₃ , CaCO ₃
Or Al ₂ O ₃ or Cr ₂ O ₃ for the purpose of controlling iHc, and pulverize in a solvent until the average particle size becomes 0.7 to 1.2 μm. The slurry containing the finely ground ferrite raw material is wet-formed while being oriented in a magnetic field. The obtained molded body is dried and sintered, and finally processed into a desired shape. There are mainly five methods for improving the performance of ferrite magnets manufactured by such a method as described below.

[0004] The first method is an atomization method. The size of the crystal grains in the sintered body is the magnetoplumbite (M) type
When the critical single domain particle diameter of the Sr ferrite magnet is close to about 0.9 μm, iHc is maximized. Just fine. However, this method has a problem in that the finer the particles, the worse the dehydration characteristics during wet molding and the lower the production efficiency.

A second method is to make the size of the crystal grains of the sintered body as uniform as possible. Ideally, the size of the crystal grains should be as uniform as possible, and the value should be the critical single domain particle size (about 0.9 μm). This is because crystal grains larger and smaller than this value lead to a decrease in iHc. The specific means of improving the performance by this method is to improve the particle size distribution of the fine powder. There is naturally a limit to the degree of improvement in magnetic properties. In recent years, an attempt to produce ferrite fine particles having a uniform particle size by a chemical precipitation method has been disclosed, but this method cannot be said to be suitable for industrial mass production.

A third method is to improve the degree of crystal orientation which affects magnetic anisotropy. Specific means in this method include adding a surfactant to the finely pulverized slurry to improve the dispersibility of the ferrite particles in the slurry, and increasing the magnetic field strength during orientation.

[0007] A fourth method is to increase the density of the sintered body. The theoretical density of Sr ferrite sintered body is 5.15g / cc
It is. The density of currently marketed Sr ferrite magnets is generally in the range of 4.9-5.0 g / cc, which corresponds to a theoretical density ratio of 95-97%. Higher densities are expected to improve Br, but higher densities beyond the above density range require expensive high-density means such as HIP. This leads to an increase in the manufacturing cost of the magnet and loses its advantage as an inexpensive magnet.

A fifth method is to use a saturation magnetization σ of a ferrite compound itself, which is a main component (main phase) of a ferrite magnet.
s or to improve the crystal magnetic anisotropy constant. Improvement of the saturation magnetization s has a possibility of directly leading to improvement of the residual magnetic flux density Br. Further, the improvement of the crystal magnetic anisotropy constant has a possibility of leading to the improvement of the coercive force iHc. Although studies on W-type ferrite having a larger saturation magnetization than conventionally produced ferrite compounds having an M-type crystal structure have been made enthusiastically, mass production has been realized due to difficulty in controlling the sintering atmosphere. Absent.

Among the above-mentioned methods for improving the performance of ferrite magnets, the first to fourth methods which are widely used at present are ferrite magnets containing a compound represented by SrO.nFe ₂ O ₃ as a main phase. It is difficult to significantly improve the performance by the first to fourth methods for the following reasons. That is, the first reason is that
The first to fourth methods have conditions that inhibit productivity, and include steps that are difficult to realize when considering mass production steps. The second reason is that the magnetic properties, especially Br
Has already reached a level close to the theoretical value, making further improvement very difficult. Next, as a result of examining the hexagonal magnetoplumbite sintered ferrite magnet described in JP-A-9-115715, it was found that it was difficult to achieve high iHc.

[0010] As a specific means of the fifth method, AO.n
A ferrite represented by Fe ₂ O ₃ (where A is Sr and / or Ba) is mixed with another metal compound (metal oxide, etc.) to separate a part of the A and Fe elements of the ferrite. It is conceivable to improve the magnetic properties by substituting with an element. The magnetism of the magnetoplumbite ferrite magnet depends on the magnetic moment of Fe ions, and the magnetic moment has a ferrimagnetic material magnetic structure in which Fe ion sites are partially arranged in an antiparallel direction. There are two ways to improve the saturation magnetization in this magnetic structure. The first method is to replace the Fe ion at the site corresponding to the magnetic moment oriented in the antiparallel direction with another element having a smaller magnetic moment than the Fe ion or a nonmagnetic element. The second method is to replace the Fe ion at the site corresponding to the magnetic moment oriented in the parallel direction with another element having a larger magnetic moment than the Fe ion.

A method for increasing the crystal magnetic anisotropy constant in the above magnetic structure is to replace Fe ions with another element having a stronger interaction with the crystal lattice. Specifically, the magnetic moment derived from the orbital angular momentum remains or is replaced with an element having a large magnetic moment.

With the above findings in mind, as a result of intensive studies for the purpose of replacing Fe ions with various elements by adding various metal compounds (metal oxides and the like), Mn, Co and Ni Is an element that significantly improves the magnetic properties. However, simply adding the above elements does not provide a sufficient effect of improving magnetic properties. This is because, when the Fe ion is to be replaced with another element, the balance of the ionic valence is lost, and a different phase is generated. In order to avoid this phenomenon, it is necessary to replace the Sr and / or Ba ion sites with another element for the purpose of charge compensation, and for that purpose, it is effective to add La, Nd, Pr, Ce, etc. is there. Thereby, a magnetoplumbite ferrite magnet having high Br or a high coercive force together therewith can be obtained.

When a compound of a rare earth element such as La and a compound of an M element such as Co are added to produce a high-performance ferrite magnet by the fifth method, usually before calcining, that is, before the ferrite-forming reaction. (Hereinafter simply referred to as “pre-addition method”). However,
Although the ferrite magnet formed by the pre-addition method has a high Br and a high iHc, particularly when R = La and M = Co, the squareness ratio (Hk / iHc) increases as the addition amount of these elements increases. A tendency to noticeably deteriorate is observed. Deterioration tendency of squareness ratio (Hk / iHc) by pre-addition method is R = L
It is also recognized when a and M = Co + Zn or M = Co + Mn. There is a problem that the demagnetization is apt to occur because the critical demagnetizing field strength is reduced due to the deterioration tendency of the squareness ratio (Hk / iHc). Ease is a problem. Therefore, it is desired to have a higher squareness ratio (Hk / iHc). Thus, a high-performance ferrite magnet that satisfies both the coercive force iHc (or the coercive force iHc and the residual magnetic flux density Br) and the squareness ratio (Hk / iHc) is desired.

Therefore, the object of the present invention is extremely useful in a wide range of magnet application fields (for example, a rotating machine for automobiles or electric equipment, a magnet roll for copying machines, etc.), and compared with conventional ferrite magnets. High coercivity iHc
(Or high coercive force iHc and residual magnetic flux density Br), and a high performance ferrite magnet having a substantially magnetoplumbite type crystal structure having a high squareness ratio (Hk / iHc), and a rotating machine using the same; It is to provide a magnet roll.

Another object of the present invention is to provide a high coercive force iHc (or a high coercive force iHc) as compared to a conventional ferrite magnet.
A high-performance ferrite magnet having a substantially magnetoplumbite-type crystal structure having a high microstructure at a grain boundary part, while having a high squareness ratio (Hk / iHc) with a residual magnetic flux density Br), and An object of the present invention is to provide a rotating machine and a magnet roll using the same.

[0016]

Means for Solving the Problems In view of the above object, as a result of earnest research, (A _1-x R _x ) O · n [(Fe _1-y M _y ) ₂ O ₃ ] (where A is Sr
And / or Ba, R is at least one rare earth element including Y, and M is at least one selected from the group consisting of Co, Mn, Ni and Zn. ), The R element and the M element are added by a post-addition method or a pre- / post-addition method to the ferrite having a basic composition represented by the following formula.
It has been found that a high-performance ferrite magnet having a substantially magnetoplumbite-type crystal structure that retains Br), has a high squareness ratio (Hk / iHc), and has a small variation in shrinkage can be obtained. The present invention has been made.

That is, the ferrite magnet of the present invention has the following general formula: (A _1-x R _x ) On · n [(Fe _1-y M _y ) ₂ O ₃ ] (atomic ratio) (where A is Sr And / or Ba, R is at least one rare earth element including Y, and M is Co, Mn, Ni and Zn.
At least one member selected from the group consisting of
And n are numbers satisfying the following conditions: 0.01 ≦ x ≦ 0.4, 0.005 ≦ y ≦ 0.04, and 5 ≦ n ≦ 6, respectively. ), Having a magnetoplumbite-type crystal structure, wherein the concentration of the R element and / or the M element is higher at the grain boundaries than within the magnetoplumbite-type crystal grains. It is characterized by.

The ferrite magnet according to a preferred embodiment of the present invention has the following general formula: (A _{1 -x} R _x ) On · [[Fe _{1 -y} M _y ) ₂ O ₃ ] (atomic ratio) , A is Sr and / or Ba, R is La,
M is Co, and x, y and n are numbers satisfying the following conditions: 0.01 ≦ x ≦ 0.4, 0.005 ≦ y ≦ 0.04, and 5 ≦ n ≦ 6, respectively. ), Having a magnetoplumbite-type crystal structure, wherein the concentration of the R element and / or the M element is higher at the grain boundaries than within the magnetoplumbite-type crystal grains. It is characterized by.

A ferrite magnet according to another preferred embodiment of the present invention has the following general formula: (A _1-x R _x ) On · [[Fe _1-y M _y ) ₂ O ₃ ] (atomic ratio) , A is Sr and / or Ba, R is at least one rare earth element including Y, and M is Co, Mn, Ni and Zn.
At least one member selected from the group consisting of
And n are numbers satisfying the following conditions: 0.01 ≦ x ≦ 0.4, 0.005 ≦ y ≦ 0.04, and 5 ≦ n ≦ 6, respectively. ) Having a basic composition represented by: It is characterized by having radial anisotropy or polar anisotropy.

The rotating machine of the present invention has the following general formula: (A _1-x R _x ) On · n [(Fe _1-y M _y ) ₂ O ₃ ] (atomic ratio) (where A is Sr and / or Or Ba, R is at least one rare earth element including Y, and M is Co, Mn, Ni and Zn.
At least one member selected from the group consisting of
And n are numbers satisfying the following conditions: 0.01 ≦ x ≦ 0.4, 0.005 ≦ y ≦ 0.04, and 5 ≦ n ≦ 6, respectively. A) a ferrite magnet having a basic composition represented by the following formula and having a magnetoplumbite crystal structure, wherein the concentration of the R element and / or the M element is higher at the crystal grain boundary than within the magnetoplumbite crystal grains. It is characterized by being.

The magnet roll of the present invention has the following general formula: (A _{1 -x} R _x ) On · n [(Fe _{1 -y} M _y ) ₂ O ₃ ] (atomic ratio) (where A is Sr and / or Or Ba, R is at least one rare earth element including Y, and M is Co, Mn, Ni and Zn.
At least one member selected from the group consisting of
And n are numbers satisfying the following conditions: 0.01 ≦ x ≦ 0.4, 0.005 ≦ y ≦ 0.04, and 5 ≦ n ≦ 6, respectively. A ferrite magnet having a basic composition represented by the following formula and having a magnetoplumbite crystal structure is used, and the concentration of the R element and / or the M element is higher at the crystal grain boundary than within the magnetoplumbite crystal grains. Concentration.

In each case, the compound of the R element is L
It is preferable to add at least one oxide, hydroxide, carbonate or organic acid salt selected from the group consisting of a, Nd, Pr and Ce. In addition, as a compound of the M element, at least one oxide selected from the group consisting of Co, Mn, Ni, and Zn;
Preferably, a hydroxide, carbonate or organic acid salt is added. It is also preferable to add only a Co compound as a compound of the M element. When a high-performance ferrite magnet is manufactured by post-addition or pre- / post-addition of the R element and M element, the R element and M element are compared with the ferrite magnet obtained by the pre-addition.
As the amount of substitution of elements (the values of x and y) increases, the deterioration tendency of the squareness ratio (Hk / iHc) is remarkably suppressed.

When R or M element is added after or before / after addition, Br and iHc may deteriorate or the shrinkage rate of the sintered body may fluctuate. To prevent this, it is preferable to add the Fe compound at the time of pulverization after calcination to such an extent that the magnetic field orientation of the compact in the compacting step is not hindered. Specifically, the post-addition amount of the iron compound is preferably set to 0.1 to 11% by weight (based on iron element) of the total iron content.

When the post-addition method is adopted, the contents (values of x and y) of the R element and the M element become large, and accordingly, the molar ratio n decreases, so that Br and iHc also deteriorate. Do you get it. It was also found that a decrease in the molar ratio n caused variations in the dimensions of the sintered body. The mechanism of the decrease in the molar ratio n is as follows. As an example of producing a ferrite magnet using the post-addition method, SrO · 5.9Fe ₂ O ₃ , that is, a molar ratio n = 5.9 represented by a composition formula of SrFe _11.8 O _18.7
About 20% of Sr ion sites
A case in which an oxide of La is added at the time of pulverization to replace with La will be examined. In this case, La
A corresponding amount of Co oxide is added simultaneously to contain approximately the same number of Co atoms as atoms. Assuming that all of them have been replaced by the M phase, the composition of the finally obtained ferrite sintered body is as follows. Sr _0.8 La _0.2 Fe _9.60 Co _0.20 O _15.7 , that is, (Sr _0.8 La _0.2 ) O · 4.9 [(Fe _0.98 Co _0.02 ) ₂ O ₃ ]. As described above, the molar ratio n of 5.9 in the calcining powder step is reduced to 4.9 by the post-addition of La oxide and Co oxide. When the molar ratio n is less than 5, the relative ratio of the component corresponding to the Fe ion site that plays a role in magnetism is reduced, and the magnetic properties are significantly reduced. At the same time, the shrinkage, which indicates the degree of dimensional change from the compact to the sintered compact, changes significantly, which causes variations in the dimensions of the ferrite magnet product obtained by processing.

It is conceivable to set the molar ratio n of the calcined powder high in advance in anticipation of the decrease in the molar ratio n due to the adoption of the post-addition method, but this measure is not effective.
Assuming that the calcined powder represented by the composition formula of SrO.n ₁ Fe ₂ O ₃ is used, La oxide and Co oxide are added in a composite during pulverization, and the following basic composition: (Sr _1-x La _x ) On-n ₂ [(Fe _1-y Co _y ) ₂ O ₃ ] (atomic ratio) (provided that 0.01 ≦ x ≦ 0.4, x / (2.6n ₂ ) ≦ y ≦ x /
(1.6n ₂ ). Suppose that a high performance ferrite magnet with x so that n ₁ = 6.5 and n ₂ = 5.9
And by selecting a value of y, so ultimately in a molar ratio n ₂ = 5.9 in the ferrite magnet to be obtained, within the scope of a preferred molar ratio n as ferrite magnets (5-6). However, the magnetic properties of the ferrite magnet in this case are very low.
The reason is because the molar ratio n ₁ of the calcined powder exceeds 6, different phase other than M phase calcined powder (αFe ₂ O _3, etc.) is generated.
Since the hetero phase is a non-magnetic phase, it deteriorates the orientation of the molded product obtained in the molding process in a wet magnetic field. Thus, when the molar ratio n ₁ of the calcined powder exceeds 6, even when the molar ratio n ₂ of the finally obtained ferrite magnets can be adjusted in the range of 5-6 by the post-addition method, Br and squareness ratio ( Hk / iHc) and the like are greatly reduced.

Therefore, without increasing the molar ratio n of the calcined powder, the molar ratio n of the sintered ferrite magnet obtained by the post-addition method or the pre- / post-addition method is set to a desired range (5 to 6). For this purpose, it is preferable to add an iron compound such as iron oxide later. It is preferable that the molar ratio n of the calcined powder before the post-addition is 5 to 6. In addition, the post-addition method or the pre / post-addition method is advantageous also because the mass production of the ferrite magnet is simple. This is because in the post-addition method or the pre / post-addition method, calcined powder of Sr and / or Ba ferrite that does not contain or has a small content of the R element and the M element can be used. More advantageously, the content of the R element and the M element is changed in units of the fine pulverization by adjusting the contents of the R element and the M element in the fine pulverization step after the calcination (that is, various contents). This is because the manufacture of a ferrite magnet having magnetic properties) becomes easy.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION [1] Ferrite Magnet The basic composition of a ferrite magnet to which the present invention can be applied is represented by the following general formula: (A _1-x R _x ) O · n [(Fe _1-y M _y ) ₂ O ₃ ] (atomic ratio) (where A is Sr and / or Ba, R is at least one rare earth element including Y, and M is Co, Mn, Ni and Zn)
At least one member selected from the group consisting of
And n are numbers satisfying the following conditions: 0.01 ≦ x ≦ 0.4, 0.005 ≦ y ≦ 0.04, and 5 ≦ n ≦ 6, respectively. ). In order to impart good magnetic properties to the ferrite magnet of the present invention, the n value (molar ratio) must be 5 or more and 6 or less. When the n value exceeds 6, a different phase (for example, a-Fe ₂ O ₃ ) other than the magnetoplumbite phase is generated, and the magnetic properties are greatly reduced.
When the n value is less than 5, Br is greatly reduced. Also x
The value is 0.01 or more and 0.4 or less. If the x value is less than 0.01, the effect of the post-addition or the pre- / post-addition is insufficient,
If it exceeds, on the contrary, the magnetic characteristics deteriorate.

In order to examine the allowable range of the addition ratio of the R element and the M element in connection with the charge compensation, as the A element,
La is selected as the Sr and R elements, and Co is selected as the M element. SrCO ₃ , Fe ₂ O ₃ , La ₂ O ₃ and Co ₃ O ₄ are represented by the following basic composition: (Sr _1-x La _x ) On [(Fe _1-y Co _y ) ₂ O ₃ ] (atomic ratio) (where x = 0.15, y = 0.77 to 2.08 × 10 ⁻² , n = 6.
0. ), Wet-mixed, and calcined in air at 1200 ° C. for 2 hours, and the magnetic properties of the obtained coarse powder were measured. As a result, the condition that the charge balance is completely satisfied,
That is, it is found that the addition ratio of x / y that satisfies y = x / 2n is not limited. When the x / ny value is in the range of 1.6 to 2.6, no substantial deterioration in the magnetic properties is recognized. When the y value deviates from x / (2.0n), it may include Fe ²⁺ , but there is no problem. On the other hand, when the value of x / ny exceeded 2.6 or was less than 1.6, a remarkable decrease in magnetic properties was observed. Therefore, the range of x / ny is 1.6 or more and 2.6 or less. When this is arranged for y, the range of y is represented by the following equation: [x / (2.6n)] ≦ y ≦ [x / (1.6n)]. In a typical example, y ranges from 0.005 to 0.04
And especially 0.005 to 0.03. Even when the content of the R and M elements satisfies y = x / (2.0n), a part of the R and / or M elements may have a high concentration near the grain boundary, but this does not cause any problem. .

In either case of the post-addition method or the pre / post-addition method, the R element is preferably at least one selected from the group consisting of La, Nd, Pr, and Ce. In one example of the ferrite magnet of the present invention, the ratio of La in R is preferably at least 50 at%, more preferably at least 70 at%, and particularly preferably at least 99 at% for improving the saturation magnetization. R may be La alone.

In another example of the ferrite magnet of the present invention, Nd, Pr, and / or R occupy R in order to improve the saturation magnetization.
The total amount of Ce is preferably at least 50 atomic%, more preferably at least 70 atomic%, particularly preferably at least 99 atomic%. In still another example of the ferrite magnet of the present invention, La, Nd, Pr, and Ce occupying R for improving saturation magnetization.
Is preferably at least 50 atomic%, more preferably at least 70 atomic%, particularly preferably
At least 99 atomic%.

The M element is preferably Co alone, or Co and Mn and / or Ni. In particular, Co and Mn and / or Ni are preferably selected as M because they have high Br and high iHc as compared with conventional ferrite magnets. Mn is
It has the effect that good magnetic properties can be obtained even when the amount of addition of the R element is smaller than that specified by the charge compensation conditions in the case of no addition. When Mn is contained, the total amount of Mn and other M elements is preferably set to 100 atomic%, and the Mn content is preferably set to 0.4 atomic% or more. For example, when M is composed of Co and Mn, the content of Mn is preferably set to 100 atomic% with Co + Mn as 100%.
The content is 0.4 to 75 atomic%, more preferably 0.7 to 60 atomic%, and particularly preferably 1 to 50 atomic%. Mn content is 0.4
If it is less than atomic%, the effect of improving Br by the inclusion of Mn is not recognized, and if it exceeds 75 atomic%, iHc is greatly reduced. When Co + Mn + Ni (Zn) is selected as the M element,
+ Mn + Ni (Zn) is 100 atomic%, and the Mn content is preferably 0.4 to 75 atomic%, more preferably 0.7 to 60 atomic%.
And particularly preferably 1 to 50 atomic%.

Further, when M is composed of Co and Ni, in order to secure a high Br and a high iHc as compared with a conventional ferrite magnet, the Ni content ratio in M is preferably set to 100 atomic% for the entire M element. The content is 10 to 75 at%, more preferably 10 to 60 at%, and particularly preferably 10 to 50 at%. If the ratio of Ni to M is less than 10 atomic%, the effect of improving Br is not remarkable, and if it exceeds 75 atomic%, iHc is greatly reduced.

Further, even when Mn and / or Ni is selected as M, the Mn content is preferably set to 0.4 to 75 atomic%, more preferably 0.7 to 60 atomic%, particularly preferably 0.7 to 60 atomic%, with Mn + Ni being 100 atomic%. When the content is 1 to 50 atomic%, a ferrite magnet having higher magnetic properties than a conventional ferrite magnet can be formed.

The ferrite magnet obtained by the post-addition method or the pre / post-addition method of the present invention has a substantially magnetoplumbite type crystal structure, wherein the R element is La and the M element is
In the case of Co, it has a residual magnetic flux density Br of 4,100 G or more at 20 ° C., a coercive force iHc of 4,000 Oe or more, a squareness ratio (Hk / iHc) of 92.3% or more, and the R element is La and the M element Is C
In the case of o and Mn and / or Zn, the residual magnetic flux density Br of 4,200 G or more and the coercive force iHc of 3,000 Oe or more at 20 ° C.
% Or more (Hk / iHc). Here, Hk, which is a parameter measured to obtain the squareness ratio, is 4πI
This is the H-axis reading at the position where 4πI is 0.95Br in the second quadrant of the (magnetization intensity) -H (magnetic field intensity) curve.
The value (Hk / iHc) obtained by dividing Hk by iHc of the demagnetization curve is defined as the squareness ratio. In the ferrite magnet of the present invention, the M element is sufficiently dissolved in the magnetoplumbite ferrite crystal grains, but the concentration at the grain boundaries tends to be higher than the concentration in the crystal grains.

[2] Manufacturing Method The basic composition is finely ground in a standard ferrite magnet manufacturing process based on mixing of raw material powder, calcining, fine grinding of calcined powder, molding, sintering, and processing. It can be formed substantially after the step. It is preferable to add an oxide or hydroxide of the R element, particularly a hydroxide, as a raw material for supplying the R element. Specifically, La ₂ O ₃ oxide such, La (OH) hydroxide _{3 etc., La 2 (CO 3) 3} · 8H 2 carbonate hydrate of O, etc., La (CH ₃ CO _{2) Three}
・ One or two organic acid salts such as 1.5H ₂ O, La ₂ (C ₂ O ₄ ) ₃・ 10H ₂ O
More than one species can be used. R elements other than La (N
Oxides, hydroxides, carbonates and organic acid salts of d, Pr, Ce) can also be used. Mixed rare earth (La, Nd, P
One or more of the oxides, hydroxides, carbonates and organic acid salts of r and Ce) can also be used. When a hydroxide of R element is added, Br, iHc and squareness ratio (Hk /
iHc) tends to be good. La, Nd, Pr and Ce
An inexpensive misch metal (mixed rare earth metal) containing 50 atom% or more of one or more of these may be used.

It is preferable to add the compound of the element M in an oxide or hydroxide state, particularly in a hydroxide state. Specifically, oxides such as Co ₃ O ₄ , Co (OH) ₂ , Co ₃ O ₄
Hydroxides such as ₁ H ₂ O (m ₁ is a positive number), carbonates such as CoCO ₃ and basics such as m ₂ CoCO ₃ .m ₃ Co (OH) ₂ .m ₄ H ₂ O One or more of carbonates (m ₂ , m ₃ , and m ₄ are positive numbers) can be used. Further, oxides, hydroxides or carbonates of Mn, Ni and Zn can also be used. When a hydroxide of the element M is added, the Br, iHc, and squareness ratio (Hk / iHc) tend to be better than those of the oxide.

In both the post-addition method and the pre / post-addition method, it is preferable to add an iron compound at the time of pulverization after calcination (particularly at the time of fine pulverization) in order to adjust the molar ratio n.
By adding an iron compound during pulverization, the y and n values can be freely adjusted in the fine pulverization step.

As an iron compound to be added later, for example, Fe
One or more oxides of ₃ O ₄ , Fe ₂ O ₃ (a-Fe ₂ O ₃ , g-Fe ₂ O ₃ ) and FeO can be used. In addition, one or more of Fe (OH) ₂ , Fe (OH) ₃ , and FeO (OH) can be used as the hydroxide of Fe. The post-addition amount of the iron compound is preferably 0.1 to 11% by weight of the total Fe amount based on the Fe element. If the amount of iron compound added is less than 0.1% by weight, the effect of addition is insufficient. If the amount exceeds 11% by weight, the magnetic field orientation during molding is reduced, and Br is greatly reduced. The molar ratio n is improved by the post-addition of the iron compound, and as a result, the squareness ratio is also improved.
For example, when the R element is La and the M element is Co, the ferrite magnet has a squareness ratio (Hk / iHc) of not less than 92.3% at 20 ° C., and the R element is La and the M element is Co and Mn and / or When Zn, squareness ratio (Hk / iHc) of 93.5% or more at 20 ° C
Having. Further, in each case, the obtained ferrite magnet shows a stable contraction rate.

Further, in the step of pulverization after calcination, the CoO · Fe ₂ O ₃ instead of the Co compound, MnO · Fe ₂ O instead of the Mn compound
₃ , ZnO.Fe ₂ O ₃ instead of Zn compound, (Co, Mn) O.Fe ₂ O ₃ instead of Co and Mn compounds, and (Mn, Zn) O. Replace Fe ₂ O ₃ with Co and Zn compounds (C
o, Zn) O.Fe ₂ O ₃ is replaced by a compound of Co, Zn, and Mn (C
By adding each of the spinel-type ferrite compounds represented by (o, Mn, Zn) O.Fe ₂ O ₃ , a decrease in the molar ratio n due to the post-addition method can be suppressed.

In the wet fine pulverization step after the calcination, the compound powder of the R element and / or the M element and, if necessary, the iron compound powder are added so as to have the same composition as the final composition of the ferrite sintered body. Wet pulverization until the average particle size of the powder becomes 0.4 to 0.9 μm. Finely ground slurry is concentrated or dried,
Crushed, then kneaded, wet formed and sintered. Average particle size
If it is crushed to less than 0.4 μm, abnormal crystal grain growth will occur during sintering, and the coercive force will decrease, and the dewatering characteristics during wet molding will deteriorate. When the average particle size of the powder exceeds 0.9 μm, many coarse crystal grains are present in the structure of the ferrite sintered body.

In the pulverizing step after the calcination, it is preferable to add SiO ₂ , CaO, CaCO _{3 and the} like as elements for controlling the sintering phenomenon. SiO ₂ is an additive that suppresses the growth of crystal grains during sintering, and its content is preferably 0.05 to 0.5% by weight based on 100% by weight of the basic composition of the ferrite magnet. If it is less than 0.05% by weight, crystal grain growth proceeds excessively during sintering, and the coercive force decreases. When the content exceeds 0.5% by weight, the growth of crystal grains is excessively suppressed, and the improvement of the degree of orientation that proceeds with the growth of crystal grains becomes insufficient, and the Br decreases. CaO is an element that promotes crystal grain growth, and its content is
0.35 to 0.85% by weight is preferable as 0% by weight. If it exceeds 0.85% by weight, crystal grain growth proceeds excessively during sintering, and the coercive force decreases. On the other hand, when the content is less than 0.35% by weight, the growth of crystal grains is excessively suppressed, the degree of orientation progressing along with the growth of crystal grains becomes insufficient, and the Br decreases.

Ferrite magnets by the before / after addition method are:
It often shows a microstructure almost intermediate between the pre-addition method and the post-addition method. In the pre / post addition method, the R element added at the time of pulverization after calcination (particularly at the time of fine pulverization) is 20% of the total R content.
When the content is at least at.%, Particularly at least 40 at.% And less than 100 at.%, For example, 50 to 80 at.%, The squareness ratio (Hk / iHc) is improved. In addition, in the pre / post addition method, the M element to be added at the time of pulverization after calcination (particularly at the time of fine pulverization) is less than the total M content.
If it is at least 20 at%, especially at least 40 at% and less than 100 at%, the squareness ratio (Hk / iHc) is remarkably improved. In order to obtain a high-performance ferrite magnet, it is important that the ferrite powder does not agglomerate in the slurry, in addition to preparing a ferrite powder whose composition is appropriately controlled. Therefore, as a result of various studies to create a state in which each particle of the ferrite powder can exist independently in the slurry, the ferrite powder was wet-milled, and then the fine powder slurry was dried or concentrated into a high-concentration slurry, followed by a dispersant. Is added and kneaded. As a result, it was found that the aggregation was released, the orientation of the ferrite magnet powder was improved, and the magnetic properties were improved. It was also found that the addition of a dispersant at the time of mixing resulted in a good dispersion state due to surface modification by adsorption of the dispersant, and further improved magnetic force.

As a dispersant, a surfactant, a higher fatty acid, a higher fatty acid soap, a higher fatty acid ester, and the like are known. It was found that the dispersibility of the ferrite particles was improved and aggregation of the ferrite particles could be effectively prevented. Although there are various polycarboxylic acid-based dispersants, ammonium carboxylate is particularly effective for improving the dispersibility of ferrite particles. The amount of the dispersant added is preferably 0.2 to 2% by weight based on the solid content of the fine powder slurry. If it is less than 0.2% by weight, the effect of addition is not recognized, and if it exceeds 2% by weight, the residual magnetic flux density decreases.

Hereinafter, the present invention will be described in detail with reference to examples.
However, the present invention is not limited to these examples.
No.Reference Examples 1 to 9, Comparative Examples 1 to 3 SrCO_Three, Fe_TwoO_Three, R element oxide and M element oxide
Basic composition: (Sr_1-xR_x) O ・ n [(Fe_1-yM_y)_TwoO_Three] (Atomic ratio) (However, n = 6.0, x = 0.15, y = x / 2n = 0.0125.)
After wet-mixing, increase the temperature at 1200 ° C for 2 hours.
It was calcined in the air. R element is similar to Sr ion
La was selected on the basis of having a radii. Also M
Have an ionic radius similar to Fe ion as an element
Select Ti, V, Mn, Co, Ni, Cu and Zn based on
Was. As Comparative Example 1, n = 6.0 in the above basic composition formula,
x = y = 0 (that is, SrO.6.0Fe _TwoO_Three)
It was calcined in the same manner. As Comparative Examples 2 and 3, the R element
Reference example except that element is La and M element is Cu or Co + Cu
A calcined powder having the same composition was produced.

Each calcined powder was dry coarsely pulverized by a roller mill, and the magnetic characteristics of each coarse powder obtained were measured by a sample vibration magnetometer. The measurement condition is that the maximum magnetic field strength is 12 kOe,
It was determined saturation magnetization σs and Hc by σ-1 / H ² plot. Table 1 schematically shows the results of identifying phases generated by X-ray diffraction. As shown in Table 1, when Cu was not included as the M element, only the X-ray diffraction peak of the magnetoplumbite phase (M phase) was observed in each case. Furthermore, from Table 1, La element is La, M element is Mn, Mn + Co, Ni, N
When i + Co is selected, it has a higher s (or higher s and Hc) than that of Comparative Example 1, and has the potential to become a high-performance ferrite magnet material when sintered into a bulk magnet. You can see that it is doing. In the present invention, La and Mn + Ni, La and Mn + Co + Ni, La
And Mn + Co + Zn, La and Co + Ni + Zn, La and Mn + Ni + Zn, La
Any combination of Mn + Co + Ni + Zn can be adopted. Among them, when Co is contained, the content ratio of Co in the M element is desirably set to 10 atomic% or more in order to provide higher Br and higher iHc as compared with the conventional case.

[0046]

[Table 1]

Example 1 SrCO ₃ and Fe ₂ O ₃ were blended to have a basic composition of SrO.nFe ₂ O ₃ (n = 5.95), mixed by wet mixing, and calcined at 1200 ° C. for 2 hours in the air. . The calcined powder was dry-pulverized with a roller mill to obtain coarse powder. Thereafter, wet pulverization was performed with an attritor to obtain a slurry containing fine powder having an average particle diameter of 0.80 μm. At this time, 0 to 2.5% by weight of La ₂ O ₃ and 0 to 2.3% by weight of CoO
Was added. As a comparative material, a slurry to which 1.3% by weight of Cr ₂ O ₃ was added in the initial stage of the coarse powder pulverization step was prepared.
In each case, at the beginning of the coarse pulverization process, 0.50% by weight of SrCO ₃ , 0.30% by weight of SiO ₂
And 0.80% by weight (0.45% by weight in terms of CaO) of CaCO ₃ was added as a sintering aid. For example, 2.50% by weight of La ₂ O ₃ and CoO
The final basic composition when adding 1.15 wt%, approximately the following _{formula: (Sr 1-x La x} ) O · n [(Fe 1-y Co y) 2 O 3] ( atomic ratio) (x = 0.15, y = x / 2n, n = 5.25).

A slurry containing 0.80 μm of each fine powder was added to 10 kOe
Wet molding in a magnetic field of 1210 ~ 1230 ℃
For 2 hours. Approximately 10 mm × 10 mm × 2
It was processed into a shape of 0 mm, and the magnetic properties were measured at 20 ° C. using a BH tracer. The results are shown in FIG. In FIG. 1, when 2.50% by weight of La ₂ O ₃ and 1.15% by weight of CoO were added (▽), iHc was particularly larger than that without (無).
It can be seen that is significantly improved. Also, it can be seen that the decrease in Br in the high iHc region is significantly smaller than in the case of adding Cr ₂ O ₃ which is usually added to increase iHc (×). Furthermore, when CoO is added alone (単 独, □) or when the balance of charge compensation is lost (◇), iHc
Was low.

According to the present embodiment, when a calcined coarse powder of a Sr ferrite magnet is prepared and then finely ground, a post-addition method of adjusting a desired basic composition by adding a La compound and a Co compound is adopted. It can be seen that Br and iHc become higher than the original Sr ferrite magnet. Then La ₂
Observation by a scanning electron microscope (SEM) was performed on a sample cut into an appropriate size from a sintered body prepared by adding O ₃ and CoO in a fine pulverization step. The magnetoplumbite type ferrite grains of this sample and the grain boundaries
Table 2 shows the SEM analysis results. From Table 2, it can be seen that La (R element) and Co (M element) are sufficiently dissolved in the magnetoplumbite ferrite crystal grains, but are also present in large numbers at the crystal grain boundaries. Further analysis of each of the crystal grain boundaries and crystal grains of this sample at 20 locations by SEM, etc.
It was found that a (R element) and / or Co (M element) tended to have a higher concentration at the crystal grain boundaries than in the magnetoplumbite ferrite crystal grains. This is obviously
This is closely related to the production of ferrite magnets by a post-addition method in which La ₂ O ₃ and CoO are added to adjust the basic composition of the sintered body in the fine pulverization step after calcination.

[0050]

[Table 2]

In this embodiment, the case where R = La and M = Co is shown. However, even in the case of a ferrite magnet formed by combining other R elements and M elements, the same microstructure as in this embodiment is obtained. Has a high coercive force iHc (or high coercive force iHc and residual magnetic flux density Br).

Example 2 This example shows that, when a ferrite magnet is manufactured by a post-addition method, fluctuations in magnetic properties and shrinkage are reduced by adding an iron compound during pulverization after calcination. . SrCO ₃ and Fe ₂ O ₃ were blended so as to have a basic composition of SrO · nFe ₂ O ₃ (n = 5.9), wet-mixed, and then calcined at 1250 ° C. for 2 hours in the air. The calcined powder was dry-pulverized with a roller mill to obtain coarse powder. Thereafter, wet pulverization was performed with an attritor to obtain a slurry containing fine powder having an average particle size of about 0.8 μm. At the beginning of the coarse powder pulverization process, based on the coarse powder weight
2.5% by weight of La ₂ O ₃ and 1.2% by weight of Co ₃ O ₄ were added, as well as 2 to 8% by weight of Fe ₃ O ₄ (magnetite). Furthermore, at the beginning of the coarse powder pulverization step, 0.1% by weight of SrCO ₃ , 1.0% by weight of CaCO ₃ and 0.3% by weight of SiO _{2 based} on the weight of the coarse powder were added as sintering aids. Each of the obtained fine powder slurries was wet-formed in a magnetic field of 10 kOe, and each of the obtained compacts was sintered at 1210 to 1230 ° C. for 2 hours. The basic composition of each of the obtained sintered bodies is substantially the following composition formula: (Sr _1-x La _x ) O · n [(Fe _1-y Co _y ) ₂ O ₃ ] (atomic ratio) (where x = 0.15 , Y = x / 2n, n = 5.32 to 5.67.)
It corresponds to. Each sintered body was processed into a shape of about 10 mm × 10 mm × 20 mm, and the magnetic properties were measured at 20 ° C. using a BH tracer. The results are shown in FIG. The vertical axis of FIG.
G), the horizontal axis is iHc (kOe).

Example 3 In the same manner as in Example 2 except that Fe ₃ O ₄ was not added, the following basic composition formula: (Sr _1-x La _x ) O · 5.20 [(Fe _1-y Co _y ) ₂ O ₃ ] (Atomic ratio) (where x = 0.15, y = x / 2n) A ferrite magnet represented by the following formula was produced. The molar ratio n of the obtained ferrite magnet was reduced to 5.20. FIG. 2 shows the magnetic characteristics measured in the same manner as in Example 2. From FIG. 2, 2 a Fe ₃ O ₄
It can be seen that when 8 wt% is added, the magnetic properties are improved as compared with the case where the added amount of Fe ₃ O ₄ is 0 wt%.
For example, when Fe ₃ O ₄ is added by 6% by weight, the amount of Fe ₃ O ₄ added is 0%.
%, The Br is improved by about 100 G as compared with the case of the same iHc value, and the iHc is increased by about 600 G as compared with the case of the same Br value. Oe had improved. Further, from the examination related to FIG. 2, the addition amount of Fe ₃ O ₄
If 0.1 to 11 wt% and (Fe element basis), as compared with the case the addition amount of Fe ₃ O ₄ is 0 weight% (Example 3) Br, it is possible to improve iHc and squareness ratio (Hk / iHc) It was also found that the shrinkage rate could be stabilized. Also, when the addition amount of Fe ₃ O ₄ is 0.1 to 11% by weight (based on Fe element), Br at 20 ° C.
High coercive force type high performance ferrite magnets with 4,150 to 4,400 G, iHc of 4,050 to 4,500 Oe and squareness ratio (Hk / iHc) of 94.5 to 96% were obtained.

Next, Fe_ThreeO_FourThe correlation between the amount of
consider. As shown in FIG.
Direction of magnetic anisotropy (Mag.) That almost matches the direction of magnetic field application
(Sh //) and shrinkage in the direction perpendicular to it
(Sh⊥), which are defined as follows. (Sh //) = (h₁−h_Two) / H₁× 100 (%), (Sh⊥) = (l₁−l_Two) / L₁× 100 (%), l₁: Length of molded body, l_Two： Sintered body length, h₁: Thickness of molded body, h_Two: Thickness of sintered body. IHc of ferrite magnet obtained in Example 2 and Example 3
To the correlation between (Sh⊥) and_ThreeO_Four(Molar ratio n)
The dependence is shown in FIG. In FIG. 4, for example, Fe _ThreeO_FourAddition
(◇) plot of 5 points with the addition of 8.0 wt%
The fluctuation range of (Sh⊥) depending on 121230 ° C. is shown. Each Fe
_ThreeO_FourIn the amount of addition, the fluctuation range of (Sh⊥) is Δ (Sh⊥).
Δ (Sh⊥) = (Maximum value of Sh⊥) − (Minimum value of Sh⊥)
Defined by According to FIG._ThreeO_FourIncrease in the amount added (molar ratio n)
And the fluctuation width of shrinkage Δ (Sh⊥)
Do you get it. Furthermore, Fe_ThreeO_FourIncrease the amount to 15% by weight
Then, the molar ratio n can be increased to about 6, and at the same time, Δ (Sh⊥)
Can be very small. Therefore, the post-addition method
Ferrite magnet according to (Sh⊥) = 11-13.5%
And Δ (Sh⊥) = (Sh⊥) within the range of 0.05 to 0.9%.
And Δ (Sh⊥) can be adjusted freely. Ferrite magnet
Δ (Sh⊥) should be increased to reduce dimensional variation of products.
Preferably 0.05 to 0.8%, more preferably 0.05 to 0.5
%, Particularly preferably 0.05 to 0.3%.

Further, at each Fe ₃ O ₄ addition amount, (Sh （/ Sh /
/) Is Δ (Sh⊥ / Sh //), and Δ (Sh⊥ / Sh /
/) = (Maximum value of Sh⊥ / Sh //) − (minimum value of Sh⊥ / Sh //). Measurement results related to FIG. _4, Fe ₃ O 4
As the addition amount (molar ratio n) increases, the fluctuation width of the shrinkage ratio Δ (S
h⊥ / Sh //) was also found to be smaller. Further Fe ₃ O ₄
If the amount added is increased to 15% by weight, the molar ratio n can be increased to about 6, and Δ (Sh⊥ / Sh //) can be made very small. Therefore, the ferrite magnet is a post-addition ferrite magnet in which (Sh⊥ / Sh //) = 1.6 to 2.4 and Δ (Sh⊥
/ Sh //) = (Sh⊥ / Sh //) and Δ (Sh⊥ / Sh //) can be freely adjusted within the range of 0.05 to 0.30. In order to suppress the dimensional variation of ferrite magnet products, Δ (ShSh / Sh //) becomes smaller and the (S
h⊥ / Sh //) = 1.9-2.2 and Δ (Sh
⊥ / Sh //) can more preferably be 0.05 to 0.20, still more preferably 0.05 to 0.15, and particularly preferably 0.05 to 0.10.

Comparative Example 4 La was selected as the R element, and Co was selected as the M element.
CO ₃ , Fe ₂ O ₃ , La ₂ O ₃ , and Co ₃ O ₄ are represented by the following basic composition: (Sr _1-x La _x ) On · n [(Fe _1-y Co _y ) ₂ O ₃ ] (atomic ratio (However, x = 0 to 0.5, y = x / 2n, n = 5.85) were blended, wet-mixed, and then calcined at 1200 ° C. for 2 hours in the air. The calcined powder was dry-pulverized with a roller mill to obtain a coarse pulverized powder. Thereafter, the slurry was finely pulverized with an attritor to obtain a slurry containing fine powder having an average particle diameter of 0.8 μm. At the beginning of the milling process, 0.40% by weight based on the fines weight
It was added SiO ₂ and 0.80 wt% of CaCO ₃ (0.45 wt% in terms of CaO) as a sintering aid. 10 k of the obtained fine powder slurry
Wet molding in a magnetic field of Oe, and the obtained molded body is 1210-1230
Sintered at ℃ for 2 hours. Approximately 10 mm x 10 mm
It was processed into a shape of × 20 mm.

Example 4 SrCO ₃ and Fe ₂ O ₃ were blended so as to have a basic composition represented by SrO.nFe ₂ O ₃ (n = 5.6), and wet-mixed.
It was calcined in air for hours. Thereafter, in the same manner as in Example 2,
By the post-addition method, 2 to 8% by weight of Fe ₃ O ₄ (magnetite) was added at the beginning of the coarse powder pulverization step to obtain a sintered ferrite magnet. The basic composition of each of the obtained sintered bodies is substantially the following composition formula: (Sr _1-x La _x ) O · n [(Fe _1-y Co _y ) ₂ O ₃ ] (atomic ratio) (where x = 0.15 , Y = x / 2n, n = 5.01 to 5.35.)
It corresponds to. Among them, the ferrite magnets of n = 5.01 to 5.20 have almost the same high magnetic properties as those of the third embodiment, and can be practically used. N is 5.20
The ferrite magnets having the same molar ratio obtained in Example 2 had almost the same high magnetic properties as the ferrite magnets obtained in Example 2.

COMPARATIVE EXAMPLE 5 SrO.nFe ₂ O ₃ was adjusted to a molar ratio n of 6.3 as shown by the basic composition formula before mixing and calcined, and then calcined. A ferrite magnet was prepared in the same manner as in Example 2 except that 6% by weight of Fe ₃ O ₄ (magnetite) was added at the beginning of the above, and the magnetic properties were measured at 20 ° C. using a BH tracer. The composition of the obtained ferrite magnet is substantially the following composition formula: (Sr _1-x La _x ) O · 5.94 [(Fe _1-y Co _y ) ₂ O ₃ ] (atomic ratio) (where y = x / 2n, x = 0.15.). The magnetic properties of this ferrite magnet were so low that they could not be plotted in FIG. In the calcined powder of this comparative example, precipitation of a-Fe ₂ O ₃ , which is considered to be because the ferrite-forming reaction did not sufficiently proceed, was recognized. It was found that the precipitation of a-Fe ₂ O ₃ deteriorates the magnetic properties of the finally obtained ferrite magnet.

Example 5 SrCO ₃ and Fe ₂ O ₃ were blended so as to have a basic composition represented by SrO · nFe ₂ O ₃ (n = 5.9), and were wet-mixed.
It was calcined in air for hours. The calcined powder was dry-pulverized with a roller mill to obtain coarse powder. Thereafter, wet milling was performed with an attritor to obtain a slurry containing fine powder having an average particle size of about 0.8 μm. At the beginning of the coarse powder milling process, 2.5% by weight of La ₂ O ₃ and 1.2% by weight of Co ₃ O ₄ are added, based on the weight of the coarse powder, and 6% by weight of Fe ₃ O ₄ (magnetite) Or 6.2
% By weight of Fe ₂ O ₃ (hematite) was added. Furthermore, at the beginning of the coarse powder pulverization process, 0.3% by weight of SrCO ₃ , 1.0% by weight of CaCO ₃ and 0.3% by weight of SiO ₂ were added as sintering aids based on the weight of the coarse powder. The obtained two kinds of fine powder slurry
Wet molding in a magnetic field of 10 kOe, and the obtained molded body is 1210 ~
Sintered at 1230 ° C for 2 hours. The two types of sintered bodies thus obtained have approximately the following compositions: (Sr _1-x La _x ) On · ([Fe _1-y Co _y ) ₂ O ₃ ] (atomic ratio) (where x = 0.15, y = x / 2n, n = 5.55 (6% by weight
Fe ₃ O ₄ added) or n = 5.50 (6.2 wt% Fe ₂ O ₃ added). ). Each of the obtained sintered bodies is approximately 10
mm × 10 mm × 20 mm and processed by BH tracer
The magnetic properties were measured at 20 ° C. FIG. 5 shows the results.
The vertical axis in FIG. 5 is Br (kG), and the horizontal axis is iHc (kOe). FIG.
From the examinations related thereto, by adding 6 wt% of Fe ₃ O ₄ (magnetite) or 6.2 wt% of Fe ₂ O ₃ (hematite), the magnetic properties and Δ (Sh
⊥) and Δ (Sh⊥ / Sh //) were found to be significantly improved. Thus, in the post-addition method, Fe ₂ O ₃ (hematite) is effective as well as Fe ₃ O ₄ (magnetite).

Example 6 SrCO ₃ and Fe ₂ O ₃ were blended so as to have a basic composition represented by SrO · nFe ₂ O ₃ (n = 5.9), and were wet-mixed.
It was calcined in air for hours. The calcined powder was dry-pulverized with a roller mill to obtain coarse powder. Thereafter, wet milling was performed with an attritor to obtain a slurry containing fine powder having an average particle size of 0.8 μm. At the beginning of the coarse powder milling process, 2.5% by weight of La ₂ O ₃ , 0.6% by weight of Co ₃ O ₄ and 0.6% by weight of ZnO are added, based on the weight of the coarse powder, and 2 to 8% by weight. Fe ₃ O ₄ (magnetite) was added. Furthermore, at the beginning of the coarse powder pulverization step, 0.1% by weight of SrCO ₃ , 1.0% by weight of CaCO ₃ and 0.3% by weight of SiO _{2 based} on the weight of the coarse powder were added as sintering aids. Each of the obtained fine powder slurries was wet-molded in a magnetic field of 10 kOe. The obtained molded body was sintered at 1210 to 1230 ° C. for 2 hours. The basic composition of each of the obtained sintered bodies is substantially the following composition formula: (Sr _1-x La _x ) On · ([Fe _1-y Co _0.5y Zn _0.5y ) ₂ O ₃ ] (atomic ratio) (However, , X = 0.15, y = x / 2n, n = 5.32 to 5.67.)
It corresponds to. Each sintered body was processed into a shape of about 10 mm × 10 mm × 20 mm, and the magnetic properties were measured at 20 ° C. using a BH tracer. FIG. 6 shows the results. The vertical axis of FIG.
G), the horizontal axis is iHc (kOe).

Example 7 A ferrite magnet was prepared in the same manner as in Example 6 except that Fe ₃ O ₄ was not added later, and its magnetic properties were measured. The basic composition of the ferrite sintered body obtained without post-addition of Fe ₃ O ₄ is substantially the following composition formula: (Sr _1-x La _x ) O · n [(Fe _1-y Co _0.5y Zn _0.5y ) ₂ O ₃ ] (atomic ratio) (where x = 0.15, y = x / 2n, n = 5.20). FIG. 6 shows the magnetic properties of this ferrite magnet. As shown in FIG. 6, when 2 to 8% by weight of Fe ₃ O ₄ is added later (Example 6), when Fe ₃ O ₄ is not added (Example 7).
It can be seen that the magnetic properties have been improved as compared with. For example, when Fe ₃ O ₄ is added in an amount of 6 to 8% by weight, the Br is improved by about 100 G as compared with the case of no addition, at the same iHc, and at the same Br. IHc is about 600 O
e had improved.

From related studies, it was found that the amount of Fe ₃ O ₄
It was found that when the content was 11% by weight (based on the Fe element), the magnetic properties were improved and the shrinkage ratio could be stabilized as compared with the case where Fe ₃ O ₄ was not added (Example 7). Specifically, the addition after the Fe ₃ O _4, at 20 ℃, Br = 4,250~
4,450 G, iHc = 3,000-3,800 Oe, squareness ratio (Hk / iHc) =
High Br type high performance ferrite magnets of 94.5-97% were obtained.
(Sh⊥) of this ferrite magnet = 11 to 13.5% and Δ
Within the range of (Sh〜) = 0.05 to 0.9%, (Sh⊥) and Δ (S
h⊥) can be adjusted freely. In order to suppress the dimensional variation of the ferrite magnet, Δ (Sh⊥) is more preferably 0.05 to 0.8%, further preferably 0.05 to 0.5%.
%, Particularly preferably 0.05 to 0.3%.
At the same time, (Sh⊥ / Sh //) = 1.6-2.4 and Δ (Sh
(Sh / Sh //) = (Sh / Sh //) and Δ (Sh / Sh //) can be freely adjusted within the range of 0.05 to 0.30. In order to suppress the dimensional variation of the ferrite magnet, Δ (Sh⊥ / Sh //) becomes smaller and the (Sh⊥ /
Sh //) = 1.9 to 2.2 and Δ (Sh⊥ / Sh
//) is more preferably 0.05 to 0.20, and still more preferably 0.
05 to 0.15, particularly preferably 0.05 to 0.10.

Example 8 SrCO ₃ and Fe ₂ O ₃ were blended so as to have a basic composition represented by SrO · nFe ₂ O ₃ (n = 5.6), and after wet mixing, the mixture was heated at 1250 ° C.
It was calcined in the air for 2 hours. Thereafter, in the same manner as in Example 6, the initial addition of the coarse powder by the post-addition method is 2 to 8
A ferrite magnet was obtained by adding Fe ₃ O ₄ (magnetite) by weight. The basic composition of each of the obtained sintered bodies is substantially the following composition formula: (Sr _1-x La _x ) On · ([Fe _1-y Co _0.5y Zn _0.5y ) ₂ O ₃ ] (atomic ratio) (However, , X = 0.15, y = x / 2n, n = 5.00-5.34.)
It corresponds to. Among them, those with n = 5.00 to 5.20 have high magnetic properties almost equal to those of the seventh embodiment, and can be sufficiently used practically. Those having n of more than 5.20 had magnetic properties equivalent to those of the same molar ratio obtained in Example 6.

Example 9 A ferrite magnet was prepared in the same manner as in Example 8 except that Fe ₃ O ₄ (magnetite) was not added at the beginning of the coarse powder pulverization step, and the magnetic properties were measured. The obtained ferrite magnet had a squareness ratio (Hk / iHc) of 93.5%.

Example 10 SrCO ₃ , Fe ₂ O ₃ , La ₂ O ₃ and Co ₃ O ₄ were made to have the following basic composition: (Sr _1-x La _x ) On · n [(Fe _1-y Co _y ) ₂ O ₃ ] (atomic ratio) (where x = 0.075, y = x / 2n, n = 5.9), wet-mixed, and calcined at 1250 ° C for 2 hours in air. The calcined powder was dry-pulverized with a roller mill to obtain coarse powder. Thereafter, the mixture was wet-pulverized with an attritor to obtain a slurry containing fine powder having an average particle size of about 0.8 μm. At the beginning of the coarse powder milling process, 1.25% by weight based on the weight of the coarse powder
La ₂ O ₃ and 0.6% by weight of Co ₃ O ₄ are added and 1-4
% By weight of Fe ₃ O ₄ (magnetite) was added. Furthermore, at the beginning of the coarse powder pulverization step, 0.1% by weight of SrCO ₃ , 1.0% by weight of CaCO ₃ and 0.3% by weight of SiO _{2 based} on the weight of the coarse powder were added as sintering aids. Each fine powder slurry was wet-formed in a magnetic field of 10 kOe. Each obtained compact is 1210-1230 ° C
For 2 hours. The basic composition of each of the obtained sintered bodies is substantially the following compositional formula: (Sr _1-x La _x ) O · n [(Fe _1-y Co _y ) ₂ O ₃ ] (atomic ratio) (where y = x / 2n, x = 0.15, n = 5.61 to 5.78.)
It corresponds to. Each sintered body was processed into a shape of about 10 mm x 10 mm x 20 mm, and the magnetic properties were measured at 20 ° C with a BH tracer. Had properties.

Example 11 A ferrite magnet was prepared in the same manner as in Example 10 except that Fe ₃ O ₄ (magnetite) was not added at the beginning of the coarse powder pulverization step, and its magnetic properties were measured. From the comparison between Examples 10 and 11, it was recognized that the magnetic properties gradually improved with an increase in the amount of Fe ₃ O ₄ added, and that Δ (Sh⊥) and Δ (Sh⊥ / Sh //) tended to decrease. Was.

Example 12 SrCO ₃ , Fe ₂ O ₃ , La ₂ O ₃ , Co ₃ O ₄ and ZnO were made to have the following basic composition: (Sr _1-x La _x ) O · n [(Fe _1-y Co _0.5y Zn _0.5y ) ₂ O ₃ ] (atomic ratio) (provided that x = 0.075, y = x / 2n, n = 5.9), wet-mixed, and tentatively set at 1250 ° C for 2 hours in air. Baked. The calcined powder was dry-pulverized with a roller mill to obtain coarse powder. After that, wet pulverization is performed with an attritor,
A slurry containing fine powder having an average particle size of 0.8 μm was obtained. 1.25% by weight, based on the weight of the coarse powder, at the beginning of the coarse pulverization process
Of La ₂ O ₃ , 0.3% by weight of Co ₃ O ₄ and 0.3% by weight of ZnO, and 1 to 4% by weight of Fe ₃ O ₄ (magnetite). Furthermore, at the beginning of the coarse powder pulverization step, 0.1% by weight of SrCO ₃ , 1.0% by weight of CaCO ₃ and 0.3% by weight of SiO ₂ were added as sintering aids. Each of the obtained finely pulverized slurries is
Wet molding was performed in a magnetic field of kOe. 1210 ~
Sintered at 1230 ° C for 2 hours. The basic composition of each of the obtained sintered bodies is substantially the following composition formula: (Sr _1-x La _x ) On · [(Fe _1-y Co _0.5y Zn _0.5y ) ₂ O ₃ ] (atomic ratio) ( However, x = 0.15, y = x / 2n, n = 5.60 to 5.77.)
It corresponds to. Each sintered body was processed into a shape of about 10 mm × 10 mm × 20 mm, and the magnetic properties were measured at 20 ° C with a BH tracer. Had. Also, Δ (Sh⊥)
Was also stable at less than 0.5%.

Example 13 A ferrite magnet was prepared in the same manner as in Example 12 except that Fe ₃ O ₄ (magnetite) was not added at the beginning of the coarse powder pulverization step. It was measured. From the comparison between Examples 12 and 13, the magnetic properties were gradually improved with the increase in the amount of Fe ₃ O ₄ added, and Δ (Sh
⊥) and Δ (Sh⊥ / Sh //) tended to be small. By adopting a post-addition method or a pre / post-addition method in which the molar ratio n can be freely adjusted while being compound-substituted with La and Co, if a composition of 0.1 ≦ x <0.2 is selected, 20
° C at Br = 4,400-4,500 G, iHc = 4,400-4,500 O
e, a high coercive force type high performance ferrite magnet with (Hk / iHc) = 95-96% can be realized.

Also, Cr ₂ O ₃ and / or Al ₂ O ₃ , which lowers Br but significantly increases iHc, are contained in an amount of 0.1 to ₂ % by weight, more preferably 0.2 to 1.5% by weight, particularly preferably 0.3 to 1.0% by weight. By adding, while maintaining high Br compared to the conventional,
A high-performance ferrite magnet with a higher coercive force can be provided. If the content of Cr ₂ O ₃ and / or Al ₂ O ₃ is less than 0.1% by weight, the effect of addition is not recognized. Therefore, the ferrite magnet of the present invention, for example, 0.1.
If ₃ to 1.0% by weight of Al ₂ O ₃ and / or Cr ₂ O ₃ is added, 20
° C at Br = 4,200-4,300 G, iHc = 4,800-5,200 Oe
It is possible to realize a high-performance ferrite magnet having a very high coercive force. The ferrite magnet of the present invention produced by adopting a post-addition method or a pre- / post-addition method in which La, Co, Zn and / or Mn are compound-substituted and the molar ratio n can be freely adjusted is obtained at 20 ° C. = 4,400-4,600 G, iHc
= 3,300-3,800 Oe, high Br with (Hk / iHc) = 95-97%
Type high performance ferrite magnet can be realized.

In the above embodiment employing the post-addition method or the pre- / post-addition method, the post-addition time of the Fe compound such as magnetite or hematite was set at the time of pulverization. The timing of post-addition of the Fe compound is not particularly limited, and the Fe compound can be post-added at any time from the state of the calcined powder after the ferrite-forming reaction until it is used for molding. When the post-addition time of the Fe compound is other than the fine pulverization step, it is preferable to use a uniform mixing means such as stirring and mixing. Further, when the compound of the R element and / or the M element is added later, it is possible at any time from the state of the calcined powder after the ferrite-forming reaction to the time of being used for molding.

Next, in the production of the ferrite magnet of the present invention, if a hydroxide, a carbonate or an organic acid salt is added instead of an oxide as a compound of the rare earth element, the reactivity is improved and the magnetic properties are improved. It has been found that it may be improved.
The first factor for realizing the improvement of the magnetic properties is R such as La
This is considered to be because the hydroxide, carbonate or organic acid salt of the element is in a finer powder than the rare earth oxide. The second factor is that when the hydroxide, carbonate or organic acid salt of the rare earth element is decomposed into oxides during the heating process during calcination or sintering, the primary crystal grains become finer and the reactivity decreases. It is thought that this is to improve. The third factor is that the decomposition reaction itself increases the reactivity. It is considered that these first to third factors are similarly present in the hydroxide of the M element such as Co. One example suitable for mass production is the R element and M during pulverization after calcination (particularly during pulverization).
The purpose is to add a hydroxide of the element or the like to finally obtain the composition of the ferrite magnet according to the present invention. R element and / or
Or the effect of improving the magnetic properties by the hydroxide of M element, etc.
This is remarkable in the case of the post-addition method. In the post-addition method, the high-temperature heating process is performed only once (sintering), so the effect of good reactivity of hydroxide, carbonate or organic acid salt is remarkable as compared with the post-addition method using oxide. It is judged that this is because it appears. As an example of this application, for example, when adding a hydroxide of element M by a post-addition method, instead of directly adding the hydroxide powder, disperse the ferrite raw material powder in an aqueous solution of CoCl ₂ and then add NaOH or NH _4. It is also possible to add an alkaline substance such as OH to form a hydroxide of the element M in a state of being formed. The same is possible for La.

[0072]Example 14 SrCO_ThreeAnd Fe_TwoO_ThreeIs SrO ・ 5.9Fe_TwoO_ThreeSo that it becomes the basic composition of
After mixing and wet mixing, calcine in air at 1200 ° C for 2 hours
did. The calcined powder is dry-pulverized with a roller mill to obtain coarse powder.
Was. Then, wet pulverization with an attritor
A slurry containing fine powder having a diameter of 0.7 to 0.8 μm was obtained. Coarse
At the beginning of the milling process, La (OH)_ThreeAnd Co (OH) _TwoAnd add
SrCO as sintering aid_Three, CaCO_ThreeAnd SiO_TwoThe coarse powder weight
0.50% by weight, 0.80% by weight and 0.45% by weight, respectively
%. The obtained fine powder slurry is placed in a magnetic field of 10 kOe.
With wet molding. The molded body was sintered at 1210-1230 ° C for 2 hours.
Was. Each of the obtained sintered bodies is (Sr_1-xLa_x) O ・ n [(Fe_1-yCo_y)
_TwoO_Three] (X = 0.15, y = x / 2n, n = 5.20)
I was Each sintered body is added to a shape of about 10 mm × 10 mm × 20 mm.
And measure magnetic properties at 20 ° C with B-H tracer
did. Table 3 shows the results.

Comparative Example 6 La ₂ O ₃ and Co ₃ were mixed at the mixing stage before calcination so that x = 0.15.
Except for adding O ₄ , the same process as in Example 14 was performed to perform the post-calcination treatment, thereby producing a ferrite magnet and measuring its magnetic properties. Table 3 shows the results.

Example 15 In the same manner as in Example 14 except that La ₂ O ₃ and Co ₃ O ₄ were added so that x = 0.15 and y = x / 2n at the beginning of the coarse powder pulverization step. Create a ferrite magnet and use a BH tracer to
Magnetic properties were measured at 0 ° C. Table 3 shows the results.

[0075]

[Table 3]

The Br, iHc and squareness ratio (Hk / iHc) in Table 3 were 20
Measured in ° C. The (Hk / iHc) value is an index not only representing the squareness ratio of the demagnetization curve but also showing the effectiveness of the substitution of La element and Co element for A ion site and Fe ion site of the M-type ferrite sintered body. It is believed that there is. Example 14 of Table 3
15 and Comparative Example 6, the La compound and Co
By adding the compound and using La (OH) ₃ and Co (OH) ₂ as the La compound and the Co compound, the squareness ratio (Hk
It can be seen that iHc can be significantly improved while maintaining good / iHc).

Example 16 By calcination in the air at 1200 ° C. for 2 hours, SrO.6.0F
A calcined powder having a basic composition represented by e ₂ O ₃ was obtained. Subsequently, dry milling was performed using a roller mill to obtain coarse powder. Thereafter, wet pulverization was performed using an attritor to obtain a slurry containing fine powder having an average particle size of 0.8 μm. At the beginning of the coarse powder pulverization process, (S
r _1-x La _x ) On · ((Fe _1-y Co _0.5y Zn _0.5y ) ₂ O ₃ ] (where x
= 0.15, y = x / 2n, n = 5.3. ), Co ₃ O ₄ , ZnO and La (OH) ₃ were added so as to obtain the basic composition represented by the formula (1). Also, at the beginning of the coarse powder pulverization process, SrCO ₃ , SiO
₂ and CaCO ₃ are 0.50% by weight, 0.40% by weight and 0.80% by weight, respectively, based on the weight of the coarse powder (0.45% by weight in terms of CaO)
Was added. Next, the obtained fine powder slurry was wet-molded in a magnetic field of 10 kOe. The obtained molded body is heated at 1210-1230 ° C for 2 hours.
Sintered for hours. Each obtained sintered body is about 10 mm × 10 mm × 20
It was processed into a shape of mm, and its magnetic properties were measured at 20 ° C. using a BH tracer. Table 4 shows the results.

[0078] As additive compound at Example 17 milling, except for using La ₂ O ₃ in place of La (OH) ₃ in the same manner as in Example 16 to prepare a ferrite magnet, at 20 ° C. by BH tracer The magnetic properties were measured. Table 4 shows the results.

Comparative Example 7 La ₂ O ₃ was used instead of La (OH) ₃ as an additive during mixing before calcination.
A ferrite magnet was produced in the same manner as in Example 16 except that was used, and the magnetic properties were measured. Table 4 shows the results.

[0080]

[Table 4]

In Table 4, Examples 16 and 17 and Comparative Example 7
From the comparison, it was found that Hk / i
Hc improves. When La, Co and Zn are added in combination,
The effectiveness of La (OH) ₃ is clear.

Example 18 SrCO ₃ , Fe ₂ O ₃ , La ₂ O ₃ and Co ₃ O ₄ were made to have the following basic composition: (Sr _{1 -x} La _x ) On · n [(Fe _{1 -y} Co _y ) ₂ O ₃ ] (where x = 0.075, y = x / 2n, n = 5.9), wet-mixed, and calcined in air at 1200 ° C for 2 hours. The calcined powder was dry-pulverized with a roller mill to obtain coarse powder. After that, wet pulverization is performed with an attritor,
A slurry containing fine powder having an average particle size of 0.7 to 0.8 μm was obtained.
X = 0.15, y = x / 2n, n
La ₂ O ₃ and Co ₃ O ₄ were post-added to make 5.55. Also, at the beginning of the coarse powder pulverization process, 0.50
Wt% of SrCO _3, 0.80 weight% of CaCO ₃ and 0.45 wt% of Si
O ₂ was added as a sintering aid. This slurry was wet-formed in a magnetic field of 10 kOe. The obtained molded body is 1210-1230 ° C
For 2 hours. Each obtained sintered body is about 10 mm × 10 mm
It was processed into a shape of × 20 mm, and its magnetic properties were measured at 20 ° C. using a BH tracer. Table 5 shows the results.

Example 19 SrCO ₃ , Fe ₂ O ₃ , La (OH) ₃ and Co ₃ O ₄ were prepared by the following basic composition: (Sr _1-x La _x ) O · n [(Fe _1-y Co _y ) ₂ O ₃ ] (atomic ratio) (provided that x = 0.075, y = x / 2n, n = 5.9), wet-mixed, and then calcined at 1200 ° C. for 2 hours in the air. The calcined powder was dry-pulverized with a roller mill to obtain coarse powder. After that, wet pulverization is performed with an attritor,
A slurry containing fine powder having an average particle size of 0.7 to 0.8 μm was obtained.
X = 0.15, y = x / 2n, n
= To be 5.55 was post-added La (OH) ₃ and Co ₃ O _4. At the beginning of the coarse powder pulverization process, SrCO ₃ , C
aCO ₃ and SiO ₂ were added at 0.50 wt%, 0.80 wt% and 0.45 wt%, respectively, based on the weight of the coarse powder. This slurry was wet-formed in a magnetic field of 10 kOe. The obtained molded body is 121
Sintered at 0-1230 ° C for 2 hours. Each obtained sintered body is about 10 m
Processed into a shape of m × 10 mm × 20 mm
The magnetic properties were measured at ° C. Table 5 shows the results.

[0084]

[Table 5]

Example 20 SrCO ₃ , Fe ₂ O ₃ , Co ₃ O ₄ , ZnO and La ₂ O ₃ were prepared by the following basic composition: (Sr _1-x La _x ) On · [[Fe _1-y Co _{0.5 y} Zn _0.5y ) ₂ O ₃ ] (atomic ratio) (however, x = 0.075, y = x / 2n, n = 6.0), and then calcined in air at 1200 ° C. for 2 hours. did. The calcined powder was dry-pulverized with a roller mill to obtain coarse powder. Thereafter, wet pulverization was performed using an attritor to obtain a slurry containing fine powder having an average particle size of 0.8 μm. At the beginning of the coarse powder pulverization step, La ₂ O ₃ , Co ₃ O ₄ and ZnO were added later so that x = 0.15, y = x / 2n, and n = 5.65. In the early stage of the coarse powder pulverization process, SrCO ₃ , SiO ₂ and CaCO ₃ were respectively used as sintering aids in an amount of 0.50% by weight based on the weight of the coarse powder,
0.40% by weight and 0.80% by weight (0.45% by weight in terms of CaO) were added. The obtained finely pulverized slurry was wet-formed in a magnetic field of 10 kOe. The obtained molded body was sintered at 1210 to 1230 ° C. for 2 hours. Each of the obtained sintered bodies was processed into a shape of about 10 mm × 10 mm × 20 mm, and the magnetic properties were measured at 20 ° C. using a BH tracer. Table 6 shows the results.

Example 21 SrCO ₃ , Fe ₂ O ₃ , Co ₃ O ₄ , ZnO and La (OH) ₃ were prepared by the following basic composition: (Sr _1-x La _x ) On [(Fe _1-y Co _0.5y Zn _0.5y ) ₂ O ₃ ] (atomic ratio) (however, x = 0.075, y = x / 2n, n = 6.0), and then tentatively set in air at 1200 ° C. for 2 hours. Baked. The calcined powder was dry-pulverized with a roller mill to obtain coarse powder. Thereafter, wet pulverization was performed using an attritor to obtain a slurry containing fine powder having an average particle size of 0.8 μm. La (OH) ₃ , Co ₃ O ₄ and ZnO were added later so that x = 0.15, y = x / 2n, and n = 5.65 at the beginning of the coarse powder pulverization step. In the early stage of the coarse powder pulverization process, SrCO ₃ , SiO ₂
And CaCO ₃ are 0.50% by weight, 0.40% by weight and 0.80% by weight, respectively, based on the weight of coarse powder (0.45% by weight in terms of CaO)
Was added. The obtained finely pulverized slurry was wet-formed in a magnetic field of 10 kOe. The obtained molded body was sintered at 1210 to 1230 ° C. for 2 hours. Each obtained sintered body is about 10 mm × 10 mm × 20 mm
And the magnetic properties were measured at 20 ° C. using a BH tracer. Table 6 shows the results.

[0087]

[Table 6]

Example 22 In order to measure the temperature characteristics of the ferrite magnet of the present invention,
The ferrite magnet produced at x = 0.15 (Example 18) was processed into a predetermined shape to produce a sample. Also, x = 0, 0.10, 0.
A ferrite magnet was prepared in the same manner as in Example 18, except that the sample was set to 20, and processed into a predetermined shape in the same manner as above to prepare a sample. Vibrating sample magnetometer (Toei Kogyo Co., Ltd., VS
M-3 type), measure the magnetic properties at -60 to + 100 ° C every 10 ° C, and obtain the temperature coefficient of Br at -60 to + 100 ° C (α)
And the temperature coefficient (β) of iHc. Table 7 shows the results.

[0089]

[Table 7]

From the data in Table 7 and the related studies, β of the ferrite magnet of the present invention complex-substituted with La and Co is about 0.
It was found to be in the range of 13 to 0.36 (% / ° C). Further, from related studies, it was found that the Curie temperature (Tc) of the ferrite magnet of the present invention represented by Table 7 is in the range of 425 ° C <Tc <460 ° C in the composition range of 0.01 ≦ x ≦ 0.4. .

Example 23 Example 20 (x = 0.15) was used to measure the temperature characteristics of the ferrite magnet of the present invention obtained by compound substitution with La, Co and Zn.
Was processed into a predetermined shape to obtain a sample. Using this sample, −60 to + 100 ° C. in the same manner as in Example 22
The magnetic properties of Br were measured, and the temperature coefficient (α) of Br and iH
The temperature coefficient (β) of c was measured. Table 8 shows the results.

[0092]

[Table 8]

From the data in Table 8, β of the ferrite magnet of the present invention complex-substituted with La, Co and Zn is 0.26 to 0.36 (% /
° C). Fig. 7 shows the EPM of the ferrite magnet of Comparative Example 4 (pre-addition method, x = 0.15, n = 5.85).
A shows the analysis results. FIG. 8 shows the ferrite magnet of Example 1 (post-addition method, x = 0.15, n = 5.25, Fe ₃ O ₄ = 0% by weight).
2 shows the results of EPMA analysis. FIG. 9 shows an EPMA analysis result of the ferrite magnet of Example 2 (post-addition method, x = 0.15, n = 5.55, Fe ₃ O ₄ = 6% by weight). Figure 10 shows that (Sr _1-x La _x ) O
[(Fe _1-y Co _y ) ₂ O ₃ ] (x = 0.10, y = x / 2n, n = 6.0)
To produce a calcined coarse powder having a basic composition of, La ₂ O during milling
₃ , ferrite magnets prepared in the same manner as in Example 10 except that predetermined amounts of Co ₃ O ₄ and Fe ₃ O ₄ were added (pre / post addition method,
(x = 0.20, n = 5.90, Fe ₃ O ₄ = 6% by weight).

Each of the EPMA analysis samples shown in FIGS. 7 to 10 was embedded in a resin so that the c-plane of the ferrite magnet became the surface, and mirror-polished using Al ₂ O ₃ polishing powder having a particle size of 0.05 μm.
It was subjected to MA line analysis. An electron beam microanalyzer (model: EPM-810) manufactured by Shimadzu Corporation as an EPMA device
Q) was used. Measurement conditions were as follows: acceleration voltage 15 kV, acceleration current 0.1
μA and the irradiation beam diameter = 1 μm. The vertical axis in FIGS. 7 to 10 is the cps (counts per count) of each element of La, Co, Sr, and Fe.
second), and the horizontal axis is the scanning distance (μm). FIG.
Each of 1010 displays the scale of the count and scan distance.
The spectral crystal of the EPMA apparatus is lithium fluoride (LiF) for line analysis of La, pentaerythritol [PET, C (CH ₂ OH) ₄ ] for line analysis of Sr, and rubidium acid phthalate [RAP for line analysis of Fe. , C ₆ H ₄ (COOH) (COORb)], and LiF in the Co line analysis.

As shown in FIGS. 7 to 10, an arbitrary
Read from EPMA analysis results for 80μm scan at position
The variation in c.p.s. of La was defined as Δ (c.p.s.).
In FIG. 7 (pre-addition method, x = 0.15, n = 5.85), Δ (c.
p.s.) = 0.119 kc.p.s. FIG. 8 (post-addition method, x
= 0.15, n = 5.25, Fe_ThreeO_Four= 0% by weight), Δ (c.p.
s.) = 0.512 kc.p.s. FIG. 9 (post-addition method, x =
0.15, n = 5.55, Fe_ThreeO _Four= 6% by weight), Δ (c.p.s.) =
0.557kc.p.s. Was obtained. Figure 10 (before / after addition method, x = 0.2
0, n = 5.90, Fe_ThreeO_Four= 6% by weight), Δ (c.p.s.) = 0.
252 kc.p.s. From Figure 7 and the related discussion,
According to the addition method, Δ (c.p.s.) = 0.07 to 0.15.
8 and 9 or the before / after addition method of FIG.
It is judged that La is distributed more uniformly than that of
You. According to the examination of FIGS. 8 and 9, according to the post-addition method, Δ
(C.p.s.) = 0.35-0.65, and La distribution is the most
It turns out that it becomes uneven. 8 and 9 that the Fe_ThreeO
_Four（(C.p.s.) tends to increase slightly with the addition of
Was done. Next, from the examination of FIG. 10, the x value and the
And / or before the y-value replacement contribution is between 20% and less than 100%
/ According to the post-addition method, Δ (c.p.s.) Is in the range of 0.15 to 0.35.
Boxed box, La distribution between post-addition and pre / post-addition
Is determined to have.

FIG. 11 shows that (Sr _1-x La _x ) O · n [(Fe _1-y Co _y ) ₂ O ₃ ]
(Atomic ratio) (provided that x = 0.10 to 0.40, y = x / 2n,
n = 5.9. 4 shows a magnetization-temperature curve of a pre-addition ferrite magnet having the basic composition of (1). The vertical axis indicates magnetization (relative value). x = 0 is the case of a ferrite magnet having a conventional composition (SrO.5.9Fe ₂ O ₃ ). The intersection between the tangent (dashed line) of each curve and the magnetization = 0 (horizontal axis) is the first Curie point (Tc ₁ ), and the intersection of each curve with the magnetization = 0 (horizontal axis) is the second Curie point (Tc ₁ ).
c ₂ ) is defined. From FIG. 11, it is clear that x = 0 to
In the magnetization-temperature curve of a 0.40 ferrite magnet, Tc ₁
Is characterized in that the curved portion surrounded by a circle is convex with respect to the tangent line (broken line) reaching.

FIG. 12 shows FIG. 9 (post-addition method, x = 0.15, n
(5.55, Fe ₃ O ₄ = 6% by weight) shows a magnetization-temperature curve measured using a sample cut out of the same ferrite magnet used in Example 1. Further, FIG. 12 shows FIG. 10 (pre / post addition method, x =
2 shows a magnetization-temperature curve measured using a sample cut out from the same ferrite magnet as used in (0.20, n = 5.90, Fe ₃ O ₄ = 6% by weight). FIG. 12 shows the Tc ₁
= 447 ° C., Tc ₂ = 453 ° C., and is characterized by including a concave portion in a curve portion surrounded by a circle with respect to a tangent line (broken line) reaching Tc ₁ . In FIG. 12, the result of addition before / after is Tc ₁ = 4
The temperature was 45 ° C., Tc ₂ = 453 ° C., and the tangent line (dashed line) leading to Tc ₁ also included a portion in which the curved portion surrounded by a circle was concave.

[0098] Example 24 SrO · 5.9Fe using calcined coarse powder having a basic composition of ₂ O _3, and 0.65μm pulverized average particle diameter, the Fe ₃ O ₄ added amount during milling
The following basic composition was obtained in the same manner as in Example 2 except that the content was 7% by weight: (Sr _1-x La _x ) O · n [(Fe _1-y Co _y ) ₂ O ₃ ] (atomic ratio) (x = 0.15, y = x / 2n, n = 5.55). Fig. 1 shows the 4πI-H curve of this ferrite magnet at 20 ° C and -40 ° C.
See Figure 3. This ferrite magnet is of the post-addition type and Fe ₃ O ₄
While adding a predetermined amount, and pulverizing the average particle size of 0.4 to 0.6.
By adjusting to conditions suitable for high Br of 5μm,
Br at 20 ° C. is 4.4 kG, iHc is 4.5 kOe,
Very high Br, iHc and squareness ratio (Hk / iHc) of 95% were achieved with a squareness ratio (Hk / iHc). The measurement results of the critical demagnetizing field strength (ΔH) at −40 ° C. of this high-performance ferrite magnet will be described below. In FIG. 13, the operating point on the BH curve in the operating line pi obtained from the magnetic circuit provided with the ferrite magnet is A, and the corresponding point on the 4πI-H curve is Q. pi = pc + 1 = 3 (pi is the permeance coefficient on the 4πI-H curve, pc is the permeance coefficient on the BH curve)
When measured under the following conditions, ΔH = 2240 as shown in FIG.
Oe was obtained. pi 'is an operation line parallel to the operation line pi. Under the condition of -40 ° C. and pi = pc + 1 = 3, the operating point magnetic flux density at the point A before ΔH is applied is (Bd ₁ ).
When ΔH = 2240 Oe is applied, the operating point moves to a point D on the BH curve corresponding to the intersection C between the operating line pi ′ and the 4πI-H curve. Thereafter, in the state of ΔH = 0 after the demagnetizing field is removed, the operating point substantially returns to the point A and overlaps. Therefore, the magnetic flux density at point A before application of ΔH (Bd ₁ ) = 3650 G, and the magnetic flux density at operation point (returning to point A) after application of ΔH and removal (Bd ₁ )
₂ ) is almost the same. Therefore, [(Bd ₁ −Bd ₂ ) / Bd ₁ ) × 10
The irreversible demagnetization rate defined by 0 (%) is almost 0%.

Comparative Example 8 According to the pre-addition method, the following basic composition was obtained: (Sr _1-x La _x ) O · n [(Fe _1-y Co _y ) ₂ O ₃ ] (where x = 0.15, y = x / A ferrite magnet was produced in the same manner as in Comparative Example 4, except that the raw materials were blended so that 2n, n = 5.85.). + 20 ℃ of this ferrite magnet
FIG. 14 shows the 4πI-H curve at −40 ° C. Since this ferrite magnet was manufactured by the pre-addition method,
Was as high as 4.4 KG and iHc was as high as 4.5 kOe, but the squareness ratio (Hk / iHc) was as poor as 76%. For this ferrite magnet with poor squareness ratio, -40 ° C
Figure 1 shows the results of measuring the critical demagnetizing field strength (ΔH ') at
See Figure 4. In FIG. 14, the operating point on the BH curve is H and the corresponding point on the 4πI-H curve is K in the operating line pi obtained from the magnetic circuit having the ferrite magnet.
pi 'and pi "are operation lines parallel to the operation line pi.
As shown in the figure, the limit applied magnetic field strength at which the demagnetization does not occur under the condition of −40 ° C. and pi = 3: ΔH ′ = 560 Oe (25% compared with ΔH in FIG. 13)
was gotten. Next, as in FIG. 13, the irreversible demagnetization rate after removing the 2240 Oe demagnetizing field was measured. -40 ° C, p
Under the condition of i = 3, when the demagnetizing field (2240 Oe) is applied, the operating point moves to the point G on the BH curve corresponding to the intersection F of the operating line pi ′ and the 4πI-H curve. Then, the demagnetizing field (2240
When Oe) is removed, the operating point substantially returns to the point H '. The operating point magnetic flux density at point H ′ (Bd ₂ ′) = 3240 G. Since the operating point magnetic flux density (Bd ₁ ′) at the point H before applying the demagnetizing field (2240 Oe) is 3640 G, the irreversible demagnetization rate is [((3640
−3240) / 3640) × 100 (%) = 11.0%, and it was found that the demagnetization was significantly larger than that in the case of FIG.

As a result of examining FIGS. 13 and 14, R = La
And M = Co, Br and 4000 at 20 ° C of 4100 G or more
In the case of the ferrite magnet of the present invention having iHc of not less than Oe and (Hk / iHc) of not less than 92.3%, ΔH is preferably not less than 1000 Oe, more preferably not more than 1500 under the condition of −40 ° C. and pi ≧ 3.
Oe or more, particularly preferably 2000 Oe or more. Furthermore, in this case, it is suitable as a radially or polar anisotropic solid cylindrical magnet or ring magnet capable of forming a symmetric or asymmetric magnetic pole having 4 to 24 poles, more preferably 4 to 16 poles. Further, the solid cylindrical magnet or ring magnet may be formed as an integral structure or a bonded structure. Further, for example, a long magnet roll for a copying machine can be constituted by an integrated structure of the ferrite magnets or a bonded structure. The contribution of the present invention to improving the performance and reducing the size of a rotating machine, a copying machine, etc. is very large.

Further, the present invention has R = La, M = Co, Zn and / or Mn, and has Br of at least 4200 G, iHc of at least 3000 Oe, and (Hk / iHc) of at least 93.5% at 20 ° C. In the ferrite magnet described above, ΔH can be greatly improved and the irreversible demagnetization rate can be suppressed to a small value. In the above embodiment, the case where the (R, M) substitution is performed on the Sr-based ferrite is described. However, the same applies to the case where the (R, M) substitution is performed on the Ba-based ferrite or the (Sr, Ba) -based ferrite. Higher coercivity iHc (or higher coercivity i
A ferrite magnet having a substantially magnetoplumbite type crystal structure having Hc and residual magnetic flux density Br) is obtained. Further, in addition to SiO ₂ and CaO, B ₂ O ₃ , B ₂
Compounds useful for improving magnetic properties such as i-compounds may be added. Further, the ferrite magnet of the present invention may contain a predetermined amount or less of unavoidable impurities in addition to the above-mentioned essential additives.

[0102]

According to the ferrite magnet of the present invention, by using a post-addition method or a pre / post-addition method in which the molar ratio n can be freely adjusted, if the rare earth element concentration has only a high microstructure at the crystal grain boundaries, It has high coercive force iHc (or high coercive force iHc and residual magnetic flux density Br) and high squareness ratio (Hk / iHc) compared to conventional ferrite magnets, Can be kept small.
The ferrite magnet of the present invention having such features is very useful for various rotating machines, actuators, and the like that require high Br and high iHc. If the Co content is less than 10 atomic%, iHc is remarkably reduced, and if it exceeds 95 atomic%, the effect of adding Zn is almost lost.

The ferrite magnet according to one embodiment of the present invention has a higher iHc than the conventional ferrite magnet while maintaining Br equal to or higher than that of the conventional ferrite magnet. Therefore, application to a motor for ABS or a starter is expected. . Since the ferrite magnet according to another embodiment of the present invention retains iHc equal to or higher than that of the conventional ferrite magnet and has a higher Br than that, it is applied to an air conditioner (air conditioner), a motor for a compressor, and the like. There is expected.

[Brief description of the drawings]

FIG. 1 is a graph showing magnetic properties of a ferrite magnet of Example 1.

FIG. 2 shows Fe in the ferrite magnets of Examples 2 and 3.
₄ is a graph showing a correlation between the amount of ₃ O ₄ added and magnetic properties.

FIG. 3 is a schematic diagram illustrating a shrinkage ratio.

FIG. 4 shows Fe in the ferrite magnets of Examples 2 and 3.
₄ is a graph showing the correlation between the amount of ₃ O ₄ added and the shrinkage.

FIG. 5 is a diagram showing the effectiveness of Fe ₂ O ₃ addition in the ferrite magnet of Example 5.

FIG. 6 is a graph showing the correlation between the amount of Fe ₃ O ₄ added and the magnetic properties in the ferrite magnet of Example 6.

FIG. 7 is a graph showing an EPMA analysis result of the ferrite magnet of Comparative Example 4 by a pre-addition method.

FIG. 8 is a graph showing an EPMA analysis result of the ferrite magnet of Example 1 by a post-addition method.

FIG. 9 is a graph showing an EPMA analysis result of the ferrite magnet of Example 2 by a post-addition method.

FIG. 10 is a graph showing an EPMA analysis result of the ferrite magnet of Example 10 by a front / post addition method.

FIG. 11 is a graph showing a magnetization-temperature curve of a ferrite magnet according to a pre-addition method.

FIG. 12 is a graph showing magnetization-temperature curves of ferrite magnets according to the post-addition method and the pre / post-addition method.

FIG. 13 is a graph showing the correlation between the squareness ratio and the demagnetization proof stress of the ferrite magnet of Example 24 by the post-addition method.

FIG. 14 is a graph showing the correlation between the squareness ratio and the demagnetization proof stress in the ferrite magnet of Comparative Example 8 using the pre-addition method.

 ──────────────────────────────────────────────────続 き Continued on the front page (31) Priority claim number Japanese Patent Application No. 10-318466 (32) Priority date November 10, 1998 (November 10, 1998) (33) Priority claim country Japan (JP) (31) Priority claim number Japanese Patent Application No. 10-332498 (32) Priority date November 24, 1998 (November 24, 1998) (33) Priority claim country Japan (JP) F-term (reference) 4G018 AA09 AA10 AA11 AA12 AA13 AA21 AA22 AA23 AA25 AB04 5E040 AA06 AB04 CA01 HB17 NN01 NN06

Claims (5)

[Claims] [Claim 1] The following general formula: (A _1-x R _x ) On ((Fe _1-y M _y ) ₂ O ₃ ] (atomic ratio) (where A is Sr and / or Ba, R is at least one of rare earth elements including Y, and M is Co, Mn, Ni and Zn.
At least one member selected from the group consisting of
And n are numbers satisfying the following conditions: 0.01 ≦ x ≦ 0.4, 0.005 ≦ y ≦ 0.04, and 5 ≦ n ≦ 6, respectively. A ferrite magnet having a basic composition represented by the formula (1) and having a magnetoplumbite crystal structure, wherein the concentration of the R element and / or the M element is higher at the crystal grain boundary than within the magnetoplumbite crystal grains. Ferrite magnet characterized by its concentration. 2. The following general formula: (A _1-x R _x ) O · n [(Fe _1-y M _y ) ₂ O ₃ ] (atomic ratio) (where A is Sr and / or Ba, R is La,
M is Co, and x, y and n are numbers satisfying the following conditions: 0.01 ≦ x ≦ 0.4, 0.005 ≦ y ≦ 0.04, and 5 ≦ n ≦ 6, respectively. A ferrite magnet having a basic composition represented by the formula (1) and having a magnetoplumbite crystal structure, wherein the concentration of the R element and / or the M element is higher at the crystal grain boundary than within the magnetoplumbite crystal grains. Ferrite magnet characterized by its concentration. 3. The following general formula: (A _1-x R _x ) O · n [(Fe _1-y M _y ) ₂ O ₃ ] (atomic ratio) (where A is Sr and / or Ba, R is at least one of rare earth elements including Y, and M is Co, Mn, Ni and Zn.
At least one member selected from the group consisting of
And n are numbers satisfying the following conditions: 0.01 ≦ x ≦ 0.4, 0.005 ≦ y ≦ 0.04, and 5 ≦ n ≦ 6, respectively. A) a ferrite magnet having a basic composition represented by: A ferrite magnet having a concentration and a radial or polar anisotropy. 4. The following general formula: (A _1-x R _x ) O · n [(Fe _1-y M _y ) ₂ O ₃ ] (atomic ratio) (where A is Sr and / or Ba, R is at least one of rare earth elements including Y, and M is Co, Mn, Ni and Zn.
At least one member selected from the group consisting of
And n are numbers satisfying the following conditions: 0.01 ≦ x ≦ 0.4, 0.005 ≦ y ≦ 0.04, and 5 ≦ n ≦ 6, respectively. A rotating machine using a ferrite magnet having a basic composition represented by the following formula and having a magnetoplumbite crystal structure, wherein the concentration of the R element and / or the M element is higher than that in the magnetoplumbite crystal grains. A rotating machine characterized by a high concentration at the grain boundaries. 5. The following general formula: (A _1-x R _x ) O · n [(Fe _1-y M _y ) ₂ O ₃ ] (atomic ratio) (where A is Sr and / or Ba, R is at least one of rare earth elements including Y, and M is Co, Mn, Ni and Zn.
At least one member selected from the group consisting of
And n are numbers satisfying the following conditions: 0.01 ≦ x ≦ 0.4, 0.005 ≦ y ≦ 0.04, and 5 ≦ n ≦ 6, respectively. A magnet roll using a ferrite magnet having a basic composition represented by the following formula and having a magnetoplumbite crystal structure, wherein the concentration of the R element and / or the M element is higher than that in the magnetoplumbite crystal grains. A magnet roll characterized by high concentration at the crystal grain boundaries.