JP2009246243A - Ferrite sintered magnet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ferrite sintered magnet sufficiently enhancing Br while maintaining HcJ that is higher enough for actual use. <P>SOLUTION: The adequate ferrite sintered magnet includes the ferrite phase having the hexagonal structure as the principal phase, and a composition of a metal element constituting the ferrite sintered magnet is expressed by the general expression (1): R<SB>x</SB>Ca<SB>m</SB>A<SB>1-x-m</SB>(Fe<SB>12-y'y"</SB>Co<SB>y'</SB>Zn<SB>y"</SB>)<SB>z</SB>. In this expression (1), x, m, y', y", and z all satisfy the conditions of 0.23≤x≤0.5, 0.12≤m≤0.39, 0.17≤y'z≤0.36, 0.01≤y"z≤0.11, 0.19≤y'z+y"z≤0.40, and 9.8≤12z≤11.7. Moreover, the composition contains an Si element as the sub element in the mass% of 0.13 to 0.48 in terms of SiO<SB>2</SB>. R is an element selected from the group formed of La, Ce, Pr, Nd, and Sm, containing La as the essential element, and A is an element selected from Sr and Ba including Sr as the essential element. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sintered ferrite magnet.

Conventionally, hexagonal Ba ferrite and Sr ferrite are known as magnetic materials used for ferrite sintered magnets. In recent years, among such ferrites, magnetoplumbite type (M type) Ba ferrite and Sr ferrite are mainly employed. M-type ferrite is represented by a general formula of AFe ₁₂ O ₁₉ , and Ba and Sr are used as an element represented by A.

  Among M-type ferrites, the element represented by A is Sr, a part of which is substituted with a rare earth element, and a part of Fe is substituted with Co. It is known that the magnetic properties are excellent (for example, see Patent Documents 1 and 2). Such M-type ferrite is required to contain La as a rare earth element. This is because La has the largest amount of solid solution with respect to hexagonal M-type ferrite among rare earth elements. Further, in Patent Documents 1 and 2, by using La as a substitution element for the element represented by A, the amount of Co that substitutes a part of Fe can be increased, and as a result, the magnetic characteristics are improved. Is disclosed.

  Here, if the element represented by A in the above general formula is Ca having an ion radius smaller than that of Sr or Ba, the crystal structure of the hexagonal ferrite cannot be obtained, so that it cannot be used as a magnetic material. However, even if the element represented by A is Ca, if a part thereof is substituted with La, the crystal structure of hexagonal ferrite can be taken. Furthermore, it is known that when a part of Fe is replaced with Co, the sintered ferrite magnet exhibits high magnetic properties (see Patent Document 3). That is, this magnetic material is M-type ferrite in which the element represented by A is Ca, a part thereof is substituted with a rare earth element containing La as an essential component, and a part of Fe is substituted with Co. .

The M-type ferrite in which the element represented by A is Ca is disclosed in Patent Documents 4 and 5 in addition to Patent Document 3 described above. According to Patent Document 4, the following formula (9) is intended to provide an oxide magnetic material and a sintered magnet that improve the residual magnetic flux density (Br) and the coercive force (HcJ) and exhibit a high squareness ratio. And an oxide magnetic material having a main phase of ferrite having a hexagonal M-type magnetoplumbite structure.
_{(1-x) CaO · (} x / 2) R 2 O 3 · (n-y / 2) Fe 2 O 3 · yMO ... (9)

  Here, in formula (9), R is at least one element selected from La, Nd, and Pr and must contain La, and M is at least one element selected from Co, Zn, Ni, and Mn. X, y, and n, which must contain Co and represent the molar ratio, are 0.4 ≦ x ≦ 0.6, 0.2 ≦ y ≦ 0.35, 4 ≦ n ≦ 6, and 1 And a composition satisfying a relational expression of 4 ≦ x / y ≦ 2.5.

Patent Document 5 discloses a sintered ferrite magnet having a composition represented by the following general formula (10) with the intention of having a high coercive force that does not decrease even if it is thin while maintaining a high residual magnetic flux density. Has been proposed.
_{A 1-x-y + a} Ca x + y R y + c Fe 2n-z Co z + d O 19 ... (10)

Here, in formula (10), the A element is Sr or Sr and Ba, the R element is at least one rare earth element including Y, and La is essential, and x, y, z, and n are calcined bodies, respectively. Represents the content and molar ratio of Ca, R element and Ca, and a, b, c and d represent the amounts of A element, Ca, R element and Co added in the calcining step of the calcined body, Each of the following conditions:
0.03 ≦ x ≦ 0.4, 0.1 ≦ y ≦ 0.6, 0 ≦ z ≦ 0.4, 4 ≦ n ≦ 10, x + y <1, 0.03 ≦ x + b ≦ 0.4, 0. 1 ≦ y + c ≦ 0.6, 0.1 ≦ z + d ≦ 0.4, 0.50 ≦ [(1-x−y + a) / (1-y + a + b)] ≦ 0.97, 1.1 ≦ (y + c) / (Z + d) ≦ 1.8, 1.0 ≦ (y + c) / x ≦ 20, and 0.1 ≦ x / (z + d) ≦ 1.2 are satisfied.
JP-A-11-154604 JP 2000-195715 A JP-A-12-223307 JP 2006-104050 A International Publication No. 2005/027153 Pamphlet

  Ferrite sintered magnets as described above are used in various applications. Therefore, in recent years, it is not always necessary to have high magnetic properties, and it is required to have properties suitable for the applications. For example, sintered ferrite magnets are increasingly applied to motor members for automobiles, OA / AV devices, home appliances, etc. In such motor applications, the output of the motor is improved. From the viewpoint, it is demanded that Br is significantly increased as compared with the prior art while maintaining a certain level of HcJ. In contrast, sintered ferrite magnets in which both Br and HcJ are improved in a well-balanced manner have been disclosed so far, but it is possible to increase the output of a motor that greatly exceeds conventional ones. A ferrite sintered magnet having such a sufficiently high Br has not yet been obtained.

  Therefore, the present invention has been made in view of such circumstances, and an object of the present invention is to provide a sintered ferrite magnet having a sufficiently increased Br while having HcJ sufficient for practical use.

In order to achieve the above object, the sintered ferrite magnet of the present invention is a sintered ferrite magnet in which a ferrite phase having a hexagonal crystal structure forms the main phase, and the composition of the metal elements constituting the sintered ferrite magnet is as follows. Represented by the formula (1),
_{R x Ca m A 1-x} -m (Fe 12-y'y '' Co y 'Zn y'') z ... (1)
(In the formula (1), R represents one or more elements selected from the group consisting of La, Ce, Pr, Nd and Sm containing La as an essential component, and A represents Sr and Ba containing Sr as an essential component. Indicates at least one element selected.)
In the formula (1), x, m, y ′, y ″ and z are represented by the following formulas (2), (3), (4), (5), (6) and (7). Satisfy all the conditions,
0.23 ≦ x ≦ 0.5 (2)
0.12 ≦ m ≦ 0.39 (3)
0.17 ≦ y′z ≦ 0.36 (4)
0.01 ≦ y ″ z ≦ 0.11 (5)
0.19 ≦ y′z + y ″ z ≦ 0.40 (6)
9.8 ≦ 12z ≦ 11.7 (7)
And, as secondary components, characterized in that it contains 0.13 to 0.48 wt% in terms of SiO ₂ and Si component.

  The sintered ferrite magnet of the present invention having the above-described configuration has a composition that contains Ca and a part thereof is substituted with an R element that requires La, and has a combination of Co and Zn as substitution elements for Fe. is doing. Therefore, Br is particularly increased as compared with the conventional case, and the HcJ is sufficiently high. The reason why Br is increased in this way is not necessarily clear. However, since Zn substituted at the Fe site is a non-magnetic ion, one reason is that the downward magnetic moment is reduced by substitution of Zn. It is thought that.

Further, in the present invention because it contains a suitable amount of SiO ₂ as subcomponent with respect to the main phase, while reducing the decrease in Br due to the SiO ₂ which is a non-magnetic component, improvement and grain sintering density by SiO ₂ The growth suppressing effect can be obtained satisfactorily. As a result, the ferrite magnet of the present invention has a high Br content while maintaining a high HcJ. Therefore, the sintered ferrite magnet of the present invention is extremely suitable for a high-power motor, for example.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the ferrite sintered magnet which has HcJ sufficient for practical use, and Br was significantly raised.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  The ferrite sintered magnet of the present embodiment is a ferrite sintered magnet in which a ferrite phase having a hexagonal crystal structure forms a main phase. Here, “the ferrite phase is the main phase” means that in a sintered ferrite magnet having a structure composed of a main phase (main phase particles) and a grain boundary portion of the main phase, this main phase is a ferrite phase. It means that there is.

  The composition of the metal element composing the ferrite sintered magnet is represented by the general formula (1). Hereinafter, the composition represented by the general formula (1) will be described.

  In the general formula (1), R represents one or more elements selected from the group consisting of La (lanthanum), Ce (cerium), Pr (praseodymium), Nd (neodymium), and Sm (samarium). However, among these elements, La is always included and is the most suitable element for improving the magnetic properties. In addition, from the same viewpoint, Pr is preferable as the element other than La.

  As for the composition ratio of each element in R, it is preferable that La is a main component from the viewpoint of further effectively improving the magnetic properties (Br and HcJ). More specifically, the composition ratio of La in R is preferably 80 to 100 atomic%, and more preferably 90 to 100 atomic%. When this composition ratio is below the lower limit, the substitution effect of R on the A site may be reduced, and sufficient magnetic properties may not be obtained as compared with the case where the composition ratio is within the above numerical range.

  A is one or more elements selected from the group consisting of Sr (strontium) and Ba (barium). However, as A, Sr is included as essential from the viewpoint of obtaining higher magnetic characteristics. The composition ratio of Sr in A is preferably 50 to 100 atomic%, and more preferably 75 to 100 atomic%.

  The ferrite sintered magnet of the present embodiment can be made particularly high in Br by including both Co and Zn as substitution elements for Fe as represented by the general formula (1). . In addition, as long as the sintered ferrite magnet is in a range that does not greatly affect the characteristics, a part of Fe may be further substituted with another element, such as Ni (nickel), Mn (manganese), Al (aluminum), Cr (chromium), etc. are mentioned.

In the general formula (1), x, m, 1-xm, (12-y′y ″) z, y′z, y ″ z and z are R, Ca (calcium), The atomic ratios of A, Fe, Co, Zn, and Fe _{12-y′y ″} Co _{y ′} Zn _{y ″} (total of Fe sites) are shown. These x, m, y ′, y ″ and z satisfy all the conditions represented by the above formulas (2), (3), (4), (5), (6) and (7). The value to be

Here, when x, which is the atomic ratio of R, is less than 0.23, the substitution effect of R on the A site is more than in the numerical range satisfying the condition represented by the above formula (2). Decreases, and magnetic properties such as Br and HcJ deteriorate. Further, when x exceeds 0.5, R which is not substituted at the A site increases as compared with the case where the condition represented by the above formula (2) is satisfied. The amount of phase formation increases and the magnetic properties are also degraded. From the same viewpoint, it is more preferable that x satisfies the condition represented by the following formula (2a).
0.30 ≦ x ≦ 0.45 (2a)

  In Ca, the composition of the magnetic material containing this Ca becomes a factor for improving the magnetic properties of the ferrite sintered magnet. That is, by adding Ca, the substitution amount of R to the A site can be increased, and accordingly, the Fe site can be sufficiently substituted with Co or Zn. This makes the magnetic properties of the ferrite sintered magnet excellent. When m is less than 0.12, the effect of improving the above-described magnetic properties by Ca is reduced as compared with the case where the condition represented by the above formula (3) is satisfied. On the other hand, if m is less than 0.12, the crystal structure of the hexagonal ferrite phase is stably present, so the amount of R dissolved in the hexagonal ferrite must be reduced. This also reduces the magnetic properties of the sintered ferrite magnet.

On the other hand, when m exceeds 0.39, the total amount of R and A in the composition decreases compared to the case where the condition represented by the above formula (3) is satisfied. When R decreases, the substitution effect of R on the A site decreases, and when A decreases, α-Fe ₂ O ₃ is easily generated. In any case, if m exceeds 0.39, the magnetic properties of the magnet will deteriorate. From the same viewpoint, it is more preferable that the condition represented by the following formula (3a) is satisfied.
0.16 ≦ m ≦ 0.35 (3a)

When y′z is less than 0.17, the substitution effect of Co on the Fe site is reduced compared to the case where the condition represented by the above formula (4) is satisfied, and Br and HcJ are sufficiently increased. It becomes difficult. If y′z exceeds 0.36, the amount of substitution of Co becomes too large compared to the case of the range of the above formula (4), and the effect of improving Br by Zn as described later is sufficiently obtained. It can no longer be obtained. From these viewpoints, y′z is more preferable when the condition represented by the following formula (4a) is satisfied.
0.18 ≦ y′z ≦ 0.31 (4a)

Furthermore, if y ″ z is less than 0.01, the effect of substituting Zn with Fe sites cannot be sufficiently obtained, and Br, which is the object of the present invention, cannot be sufficiently improved. On the other hand, if it exceeds 0.11, the Co substitution effect is hindered and HcJ tends to be insufficiently maintained. From the standpoint of greatly increasing Br while maintaining HcJ sufficiently, y ″ z is particularly preferable if it further satisfies the condition represented by the following formula (5a).
0.01 ≦ y ″ z ≦ 0.08 (5a)

y′z + y ″ z indicates the total atomic ratio of Co and Fe substituted at the Fe site. When this value is less than 0.19, both the substitution effect of Co and Zn is reduced. Sufficient magnetic properties cannot be obtained. On the other hand, if it exceeds 0.40, the substitution amount of Co and Zn to the Fe site exceeds the limit, so that a heterogeneous phase or the like is generated and the magnetic properties are deteriorated. From the same viewpoint, it is more preferable that y′z + y ″ z satisfies the condition represented by the following formula (6a).
0.25 ≦ y′z + y ″ z ≦ 0.38 (6a)

When 12z is less than 9.8, the atomic ratio of Fe sites is small, so the A site element in the crystal structure of the hexagonal ferrite phase becomes redundant. As a result, since the element represented by A is discharged from the ferrite phase as the main phase, the nonmagnetic grain boundary component is unnecessarily increased and the magnetic properties are deteriorated. On the other hand, when 12z exceeds 11.7, the composition ratio of Fe with respect to the element represented by A becomes high, and a soft magnetic spinel ferrite phase containing α-Fe ₂ O ₃ , Co, or Zn is easily generated. As a result, the magnetic properties are degraded. From the same viewpoint, 12z is more preferable if the condition represented by the following formula (7a) is satisfied.
10.4 ≦ 12z ≦ 11.6 (7a)

The general formula (1) indicates the composition ratio of R, Ca, A, Fe, Co, and Zn which are metal elements in the sintered ferrite magnet. The sintered ferrite magnet naturally contains O (oxygen) as a constituent element. Therefore, the composition of the sintered ferrite magnet including oxygen is represented by the following general formula (1a).
_{R x Ca m A 1-x} -m (Fe 12-y'y '' Co y 'Zn y'') z O 19 ... (1a)

  In the sintered ferrite magnet of the present invention, the ratio of the hexagonal M-type ferrite phase (hereinafter also referred to as “M phase”) represented by the general formula (1a) is preferably 95 mol% or more. The composition ratio of oxygen is affected by the composition ratio of each metal element and the valence of each element (ion), and increases or decreases so as to maintain electrical neutrality in the crystal. Further, in the firing step described later, oxygen deficiency may occur when the firing atmosphere is a reducing atmosphere. In the above general formula (1a), the number of oxygen atoms is 19, but may be slightly deviated depending on these factors.

The sintered ferrite magnet of the present embodiment has the above-described composition and contains a Si (silicon) component as a subcomponent. Here, the Si component includes both Si atoms themselves and Si-containing compounds (SiO _{2 and the} like). In the ferrite sintered magnet, Si may be contained in the main phase or may be contained in the grain boundary part, but it is preferable that it exists exclusively in the grain boundary part.

By including the Si component as an accessory component, the sintered ferrite magnet has improved sinterability, and the magnetic properties are well controlled, and the crystal grain size of the sintered body is appropriately adjusted. It will be a thing. A suitable content of the Si component is 0.13 to 0.48% by mass in terms of SiO _{2 as} described above. When the content of Si component is too large, a large amount of Si component, which is a nonmagnetic component, is contained in the sintered ferrite magnet, so that the magnetic properties (particularly Br) are lowered. On the other hand, even if there are too few Si components, the above-mentioned favorable effect is not acquired and HcJ falls disadvantageously. From this viewpoint, the content of the Si component is more preferably to be 0.25 to 0.45 mass% in terms of SiO _2.

The sintered ferrite magnet of the present embodiment, in addition to containing SiO ₂ as subcomponent may further contain other auxiliary ingredients. For example, first, a Ca component may be included as a subcomponent. However, the sintered ferrite magnet of this embodiment includes Ca as a component constituting the ferrite phase that is the main phase as described above. Therefore, when Ca is contained as a subsidiary component, for example, the amount of Ca analyzed from the sintered body is the total amount of the main phase and the subsidiary component. Therefore, when the Ca component is used as the subcomponent, the atomic ratio m of Ca in the general formula (1) is a value including the subcomponent. Since the range of the atomic ratio m is specified based on the composition analyzed after sintering, it can be applied both when the Ca component is included as a subcomponent and when it is not included.

Moreover, the ferrite sintered magnet may contain B ₂ O ₃ as a subcomponent. Thereby, the calcination temperature and the sintering temperature can be lowered, which is advantageous in production. The content of B ₂ O ₃ is preferably 0.5% by mass or less with respect to the total amount of the sintered ferrite magnet, from the viewpoint of maintaining high saturation magnetization.

Furthermore, it is preferable that a ferrite sintered magnet does not contain alkali metal elements such as Na (sodium), K (potassium), and Rb (rubidium) from the viewpoint of maintaining high saturation magnetization. However, an alkali metal element may be contained as an inevitable impurity. In that case, these content are oxides _{(Na 2 O, K 2 O} , Rb 2 O) in terms of, be based on the total amount of the ferrite sintered magnet is 1.0 wt% or less Is preferred.

  Furthermore, ferrite sintered magnets include, for example, Ga (gallium), In (indium), Li (lithium), Mg (magnesium), Ti (titanium), Zr (zirconium), Ge (germanium), and Sn (tin). V (vanadium), Nb (niobium), Ta (tantalum), Sb (antimony), As (arsenic), W (tungsten), Mo (molybdenum), and the like may be contained as oxides. These contents are converted to oxides of stoichiometric composition and are 5.0% by mass or less of gallium oxide, 3.0% by mass or less of indium oxide, respectively, based on the total amount of the sintered ferrite magnet. Lithium 1.0 mass% or less, Magnesium oxide 3.0 mass% or less, Titanium oxide 3.0 mass% or less, Zirconium oxide 3.0 mass% or less, Germanium oxide 3.0 mass% or less, Tin oxide 3.0 mass% % Or less, vanadium oxide 3.0% or less, niobium oxide 3.0% or less, tantalum oxide 3.0% or less, antimony oxide 3.0% or less, arsenic oxide 3.0% or less, tungsten oxide It is preferable that they are 3.0 mass% or less and molybdenum oxide 3.0 mass% or less.

The sintered ferrite magnet of the present embodiment has the specific composition described above, and in particular includes Co and Zn as a substitution element for Fe at a predetermined ratio, and includes a specific amount of SiO ₂ as a subcomponent. Therefore, it is possible to exhibit Br that is higher than the conventional one while having HcJ sufficient for practical use.

  Therefore, this ferrite sintered magnet can greatly contribute to high output when applied to a motor, and is extremely suitable for a motor that requires high output. Motors to which ferrite sintered magnets are applied include, for example, fuel pumps, power windows, ABS (anti-lock brake system), fans, wipers, power steering, active suspensions, starters, Examples include motors for automobiles such as door locks and electric mirrors. Also for FDD spindle, VTR capstan, VTR rotary head, VTR reel, VTR loading, VTR camera capstan, VTR camera rotary head, VTR camera zoom, VTR camera focus, radio cassette etc. It is also suitable for motors for OA / AV equipment such as CD / DVD / MD spindle, CD / DVD / MD loading, and CD / DVD optical pickup. Furthermore, motors for home appliances such as an air conditioner compressor, a freezer compressor, an electric tool drive, a dryer fan, a shaver drive, an electric toothbrush, and the like are also included. Furthermore, it can also be used as a member of a motor for FA devices such as a robot shaft, joint drive, robot main drive, machine tool table drive, and machine tool belt drive.

  Further, the sintered ferrite magnet of the present embodiment can be applied to applications other than motors. For example, a generator for a motorcycle, a magnet for a speaker / headphone, a magnetron tube, a magnetic field generator for MRI, a clamper for a CD-ROM. It can be applied as a member for a distributor sensor, an ABS sensor, a fuel / oil level sensor, a magnet latch, an isolator or the like. Alternatively, it can also be used as a target (pellet) when the magnetic layer of the magnetic recording medium is formed by vapor deposition or sputtering.

  FIG. 1 is a schematic perspective view showing an example of the shape of a sintered ferrite magnet having the above-described composition. The ferrite sintered magnet 10 forms a column having an arc cross section, and its corners are chamfered. The ferrite sintered magnet 10 is suitably used as a motor member, for example. However, the shape of the ferrite sintered magnet of the present invention is not limited to this, and may be a shape suitable for each application described above.

  Next, a preferred embodiment of the method for manufacturing a ferrite sintered magnet as described above will be described. This method for producing a sintered ferrite magnet includes a blending step, a calcination step, a coarse pulverization step, a fine pulverization step, a forming step in a magnetic field, and a firing step.

<Mixing process>
First, in the blending step, the starting raw material powder of the sintered ferrite magnet is weighed to a predetermined ratio, and then mixed and pulverized by a wet attritor, a ball mill or the like to obtain a raw material composition powder. What is necessary is just to adjust the time of mixing and a grinding | pulverization process suitably according to the quantity etc. of a starting raw material, for example, is about 0.1 to 20 hours. Examples of the starting material include compounds having one or more metal elements constituting the sintered ferrite magnet. Specific examples include metal element oxides constituting ferrite sintered magnets, metal element hydroxides, carbonates, and nitrates that can be converted into oxides by firing. The average particle size of the starting material is not particularly limited, but is preferably about 0.1 to 2.0 μm. In the blending step, it is not necessary to mix all of the starting materials, and some of them may be added and mixed after the calcining step described later. Moreover, it is not necessary to use the total amount of starting material corresponding to the desired composition of the sintered ferrite magnet, and the same starting material may be added separately in the blending step and after the calcining step.

<Calcination process>
In the calcining step, the raw material composition powder obtained in the blending step is calcined to obtain a calcined body. Calcination can be performed in an oxidizing atmosphere such as in the air. The calcination temperature is preferably 1100 to 1450 ° C, more preferably 1150 to 1400 ° C, and further preferably 1200 to 1350 ° C. After the calcination step, the stabilization time until the pulverization step is started is preferably 1 second to 10 hours, and more preferably 1 second to 5 hours. The calcined body after the calcining step usually contains 70 mol% or more of the M phase. The average primary particle diameter of the M phase is preferably 10 μm or less, more preferably 5.0 μm or less.

<Crushing process>
Since the calcined body is generally in the form of granules, lumps, etc., it cannot be formed into a desired shape as it is. Therefore, in the pulverization step, the calcined body is pulverized so that it can be formed into a desired shape. In this pulverization step, ferrite phase crystal particles having a suitable shape can be formed by appropriately adjusting the pulverization conditions. In the pulverization step, starting raw material powder, other additives, and the like may be further added and mixed for the purpose of adjusting the composition of the sintered ferrite magnet to a desired one. In the present invention, the starting raw material powder and additives added after the calcination step are collectively referred to as “post-additives”. This pulverization step preferably comprises (1) a coarse pulverization step and (2) a fine pulverization step.

(1) Coarse pulverization step In the coarse pulverization step, a granulated or massive calcined body is coarsely pulverized to obtain a coarsely pulverized material. As described above, since the calcined body is generally in the form of granules, lumps, etc., it is preferable to coarsely pulverize the calcined body in this state. The coarse pulverization is performed using a known pulverizer such as a vibration mill until the average particle size of the coarsely pulverized material is about 0.5 to 5.0 μm.

(2) Fine pulverization step In the fine pulverization step, the coarsely pulverized material is further pulverized to obtain a finely pulverized material. For fine pulverization, for example, a known pulverizer such as a wet attritor, ball mill, or jet mill is used, and the average particle size of the fine pulverized material is 0.05 to 0.5 μm, preferably 0.1 to 0.4 μm, More preferably, it is performed until it becomes 0.1 to 0.3 μm. The specific surface area of the obtained milled material is preferable to be 9~20m ² / g, more preferably a 10 to 15 m ² / g. When the specific surface area is less than 9 m ² / g, the density, orientation degree, and squareness ratio Hk / HcJ of the obtained sintered ferrite magnet tend to decrease due to the lower degree of fine grinding. Moreover, when this specific surface area exceeds 20 m < ² > / g, it will exist in the tendency for the water draining property in wet shaping | molding to deteriorate, and to become difficult to shape | mold. In the present specification, the specific surface area is determined by the BET method. Although it depends on the pulverization method, the pulverization time may be, for example, about 30 minutes to 25 hours in the case of using a wet attritor, and about 20 to 60 hours in the case of wet pulverization with a ball mill.

  The Si component, which is an essential subcomponent in the ferrite sintered magnet of the present embodiment, may be added in the blending step, but is more preferably added in the pulverization step as a post-additive. Moreover, it is preferable to add subcomponents other than the Si component as described above as a post-additive in the pulverization step. By adding these post-additives, it is possible to improve the sinterability, control the magnetic properties, adjust the crystal grain size of the sintered body, and the like. From these viewpoints, the post-additive is preferably added particularly in this (2) pulverization step.

In the present embodiment, in order to increase the magnetic orientation of the sintered ferrite magnet, an acyclic saturated polyhydric alcohol represented by the general formula C _n (OH) _n H _{n + 2} is added in the pulverization step. May be. Here, in said general formula, n showing carbon number becomes like this. Preferably it is 4-100, More preferably, it is 4-30, More preferably, it is 4-20, Most preferably, it is 4-12. As this acyclic saturated polyhydric alcohol, for example, sorbitol is suitable. Acyclic saturated polyhydric alcohols may be used alone or in combination of two or more. Furthermore, in addition to the acyclic saturated polyhydric alcohol, other known dispersants may be added in the pulverization step.

  (2) In the pulverization step, an unsaturated polyhydric alcohol and / or a cyclic polyhydric alcohol may be added in addition to or instead of the acyclic saturated polyhydric alcohol. These polyhydric alcohols are advantageous in improving the degree of magnetic orientation when the number of hydroxyl groups in the molecule is 50% or more of the carbon number n. However, it is preferable that the number of hydroxyl groups is large, and it is most preferable that the number of hydroxyl groups is the same as the number of carbon atoms. The addition amount of the polyhydric alcohol is preferably 0.05 to 5.0% by mass, more preferably 0.1 to 3.0% by mass, with respect to the coarsely pulverized material and the finely pulverized material which are the addition objects. More preferably, it is 0.3-2.0 mass%. In addition, the added polyhydric alcohol is thermally decomposed and removed in the baking step after the forming step in the magnetic field described later.

  In the pulverization step, only one pulverization process may be performed. The fine pulverization step may include a first fine pulverization step and a second fine pulverization step. Further, a powder heat treatment step may be provided between the first pulverization step and the second pulverization step. Hereinafter, the first pulverization step, the powder heat treatment step, and the second pulverization step will be described.

(First fine grinding step)
In the first fine pulverization step, the first finely pulverized material is obtained by wet or dry pulverization of the coarsely pulverized material using a known pulverizer such as an attritor, ball mill or jet mill. The average particle size of the first finely pulverized material is preferably 0.08 to 0.8 μm, more preferably 0.1 to 0.4 μm, and further preferably 0.1 to 0.2 μm. The first pulverization step aims to reduce coarse particles as much as possible and to refine the structure after sintering in order to improve magnetic properties. The specific surface area of the first finely pulverized material is preferably 18 to 30 m ² / g. The pulverization time in the first fine pulverization step depends on the pulverization method, but is preferably 60 to 120 hours per 220 g of the coarsely pulverized material when wet pulverized the coarsely pulverized material with a ball mill.

  In order to improve the coercive force and adjust the particle size of the sintered crystal particles, Si component powder or other post-additive powder may be added prior to the first fine grinding step. Good.

(Powder heat treatment process)
In the powder heat treatment step, the first finely pulverized material is heated at 600 to 1200 ° C., more preferably 700 to 1000 ° C., and preferably 1 second to 100 hours to obtain a heat treated material. In the manufacturing process of the ferrite sintered magnet of the present embodiment, ultra fine powders that are powders of less than 0.1 μm are inevitably generated through the first fine grinding process. If this ultrafine powder is present, problems may occur in the subsequent molding process in a magnetic field. For example, when there is a large amount of ultrafine powder during wet molding, problems such as poor water drainage and molding cannot occur. Therefore, in this embodiment, it is preferable to perform the powder heat treatment step before the magnetic field forming step. This powder heat treatment step includes ultrafine particles of less than 0.1 μm produced through the first fine pulverization step, as well as ultrafine particles and fine particles having a larger particle size (for example, a particle size of 0.1 to 0.2 μm). The purpose is to reduce the amount of ultrafine powder. By this heat treatment, ultrafine powder is reduced and the moldability can be improved. The heat treatment atmosphere at this time may be an air atmosphere.

(Second fine grinding step)
In the second fine pulverization step, the heat-treated material is wet or dry pulverized using a known pulverizer such as an attritor, ball mill or jet mill to obtain a second fine pulverized material. The average particle size of the second finely pulverized material is preferably 0.5 μm or less, more preferably 0.05 to 0.4 μm, and further preferably 0.1 to 0.3 μm. This second pulverization step aims to adjust the particle size, remove neck growth, and improve the dispersibility of additives.

The specific surface area of the second milling material, preferable to be 9~20m ² / g, more preferably a 10 to 15 m ² / g. When the specific surface area is adjusted within this numerical range, even if ultrafine powder is present, the amount thereof is extremely small, and the degree of adverse effects on the moldability becomes very low. By undergoing the first and second pulverization steps and the powder heat treatment step between these steps, the moldability is improved and the structure of the sintered ferrite magnet can be further refined. Further, the degree of orientation of the sintered ferrite magnet is improved, and the particle size distribution of the crystal particles can be improved.

  The pulverization time in the second pulverization step depends on the pulverization method, but in the case of wet pulverization with a ball mill, it may be 10 to 40 hours per 200 g of the heat treatment material. However, the pulverization conditions in the second fine pulverization step are preferably conditions that are milder than the pulverization conditions in the first fine pulverization step, that is, conditions that are more difficult to pulverize. This is because if the second fine grinding step is performed under the same severe conditions as the first fine grinding step, ultrafine powder will be generated again, and it is already desired in the first fine grinding step. This is because a finely pulverized material having a particle size is almost obtained. It should be noted that whether or not the pulverization conditions are milder may be determined based on mechanical energy input during pulverization, not limited to the pulverization time.

  In order to improve the coercive force and adjust the grain size of the sintered crystal particles, Si component powder or other post-additive powders are added prior to the second pulverization step. May be.

  By passing through the pulverization process as described above, a finely pulverized material to be used in a magnetic field forming process described later is obtained. Thus, it is preferable to obtain a slurry containing a finely pulverized material. Then, the obtained slurry can be concentrated to a predetermined concentration to obtain a slurry for wet molding. Concentration may be performed by centrifugation, filter press, or the like. In this case, it is preferable that the finely pulverized material accounts for about 30 to 80% by mass in the slurry for wet molding. As the dispersion medium, water is preferable. In addition to water, surfactants such as gluconic acid and / or gluconate and sorbitol may be contained in the dispersion medium. The dispersion medium is not limited to water and may be a non-aqueous dispersion medium. Examples of the non-aqueous dispersion medium include organic solvents such as toluene and xylene. When using a non-aqueous dispersion medium, it is preferable to contain a surfactant such as oleic acid in the dispersion medium.

<Molding process in magnetic field>
In the forming step in the magnetic field, the finely pulverized material obtained in the above-described pulverizing step (the second finely pulverized material after the second finely pulverizing step) is used, and dry or wet forming is performed while applying the magnetic field. To obtain a molded body. In order to further increase the degree of magnetic orientation, wet molding is preferred. In the case of wet molding, a slurry for wet molding containing a finely pulverized material is molded in a magnetic field. The molding pressure is preferably 0.1 to 0.5 ton / cm ² , and the applied magnetic field is preferably 5 to 15 kOe.

<Baking process>
Thereafter, in the firing step, the compact is fired to obtain a sintered ferrite magnet that is a sintered body. Firing can be performed in an oxidizing atmosphere such as the air. By adjusting each firing condition in this firing step, the density of the sintered ferrite magnet and the size and shape of the ferrite phase crystal particles can be suitably controlled.

  The firing temperature is preferably 1100 to 1220 ° C, and more preferably 1140 to 1200 ° C. If the firing temperature is less than the above lower limit, it becomes difficult to obtain a desired density due to insufficient sintering, and Br of the sintered ferrite magnet tends to decrease. If the firing temperature exceeds the upper limit, crystal grains grow excessively, and the ferrite sintered magnet HcJ and the squareness ratio Hk / HcJ tend to decrease. Moreover, it is preferable to make time to hold | maintain at the stable baking temperature to about 0.5 to 3 hours.

  When a molded body is formed by wet molding, cracks may occur in the molded body if the molded body is heated rapidly without being sufficiently dried. Therefore, in the initial stage of the firing step, it is preferable to gradually volatilize and remove the dispersion medium such as water from the molded body. As a specific example, in the initial stage of the firing step, the molded body is heated at a slow temperature increase rate of about 10 ° C./hour from room temperature to about 100 ° C. to sufficiently dry the molded body. Thereby, generation | occurrence | production of the crack of a molded object can be suppressed more. In addition, when a surfactant or the like is added to the dispersion medium, it is preferable to perform a degreasing process after removing the dispersion medium. As a specific example, the temperature rise rate is about 2.5 ° C./hour, for example, in the temperature range of about 100 to 500 ° C. in the temperature raising process in the firing step. Thereby, the surfactant can be sufficiently removed.

  In addition, the conditions in each step of the manufacturing method of the above-mentioned ferrite sintered magnet is a suitable range for obtaining the ferrite sintered magnet of the present invention, and if the ferrite sintered magnet can be manufactured, It is not limited to the said conditions.

The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. The present invention can be variously modified without departing from the gist thereof.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to these Examples.

[Method for producing sintered ferrite magnet]
First, steps common to the method for manufacturing each ferrite magnet sample shown below will be described. In the following description of the method for manufacturing each sample, only the manufacturing conditions that differ for each sample will be described.

(Mixing process)
First, as a starting material, a metal compound powder constituting a ferrite sintered magnet was prepared. Here, as starting materials for La, Ca, Sr, Fe, Co and Zn, lanthanum hydroxide (La (OH) ₃ ), calcium carbonate (CaCO ₃ ), strontium carbonate (SrCO ₃ ), iron oxide (Fe ₂₎ O ₃ ), cobalt oxide (Co ₃ O ₄ ), and zinc oxide (ZnO) were used, and these were appropriately selected and used. Then, these powders are mixed with x, m, 1-xm, (12-y′y ″) z, y′z, y ″ z and z (hereinafter simply referred to as “ The composition of each element ”) was weighed for each sample so that a predetermined atomic ratio was obtained. Subsequently, these starting raw material powders were mixed and pulverized by a wet attritor to obtain a slurry-like raw material composition.

(Calcination process)
After drying the raw material composition obtained above, a calcining treatment was performed in the air at 1300 ° C. for 2.5 hours to obtain a calcined body.

(Crushing process)
First, in the coarse pulverization step, the calcined body was coarsely pulverized with a small rod vibration mill to obtain a coarsely pulverized material.

  Next, the coarsely pulverized material was subjected to a two-stage fine pulverization process by a wet ball mill. In the first fine pulverization step, the coarsely pulverized material and water were mixed and then finely pulverized for 88 hours to obtain a first finely pulverized material. Thereafter, the first finely pulverized material was heated in the atmosphere at 800 ° C. for 1 hour to obtain a heat-treated material.

Subsequently, in the second pulverization step, water and sorbitol are added to the heat treatment material, and a predetermined post-additive (starting raw material for adjusting SiO ₂ as a subcomponent or composition) is appropriately added. The slurry containing the second finely pulverized material was obtained by fine pulverization for 25 hours using a wet ball mill.

(Molding process in magnetic field)
Next, the solid content concentration of the slurry containing the second finely pulverized material was adjusted, and molding was performed in a magnetic field using a wet magnetic field molding machine, to obtain a cylindrical molded body having a diameter of 30 mm and a height of 15 mm. At this time, the applied magnetic field was 12 kOe.

(Baking process)
Thereafter, the molded body was sufficiently dried at room temperature in the air, and then fired at 1180 ° C. for 1 hour to obtain a sintered ferrite magnet as a sintered body.

[Samples 1 to 34]
In manufacturing the sintered ferrite magnets of Samples 1 to 34, the following manufacturing method A, B, or C was performed.

(Production method A)
In the blending step, starting materials of La, Ca, Sr, Fe, and Co were prepared, and these were weighed and used so that the composition of each element had the atomic ratio shown in Table 1.

In the pulverization step, La (OH) ₃ , ZnO, CaCO ₃ , Fe ₂ O ₃ and SiO ₂ were added as post-additives during the second fine pulverization step. The addition amount of the post-additive, the content of the composition and SiO ₂ of each element in the main phase was adjusted to become as shown in Table 2.

  This manufacturing method is an example in the case where a Zn component and a Co component, which are Fe site substitution elements, are added in the grinding step.

(Production method B)
In the blending step, starting materials of La, Ca, Sr, Fe, and Co were prepared, and these were weighed and used so that the composition of each element had the atomic ratio shown in Table 1.

In the pulverization step, CaCO ₃ and SiO ₂ were added as post-additives during the second fine pulverization step. The addition amount of the post-additive, the content of the composition and SiO ₂ of each element in the main phase was adjusted to become as shown in Table 2.

  This manufacturing method is an example in the case where the Zn component is not added among the substitution elements at the Fe site.

(Manufacturing method C)
In the blending step, starting materials of La, Ca, Sr, Fe, and Co were prepared, and these were weighed and used so that the composition of each element had the atomic ratio shown in Table 1.

In the pulverization step, La (OH) ₃ , ZnO, CaCO ₃ , Fe ₂ O ₃ and SiO ₂ were added as post-additives during the second fine pulverization step. The addition amount of the post-additive, the content of the composition and SiO ₂ of each element in the main phase was adjusted to become as shown in Table 2.

  This manufacturing method is an example in which a Co component that is a substitution element for Fe sites is added in the blending step, and a Zn component is added in the grinding step.

(composition)
In the manufacturing methods A to C described above, the composition of the raw material compositions a1 to a4 prepared in the blending step is as shown in Table 1.

In addition, Table 2 shows the results of determining the composition of each of the sintered ferrite magnets of Samples 1 to 34 obtained above by fluorescent X-ray quantitative analysis. Table 2 also shows the raw material composition used in the production of each sample and the types (A to C) of the production method.

(Evaluation of sintered ferrite magnet)
The magnetic properties (residual magnetic flux density Br, coercive force HcJ, and squareness ratio Hk / HcJ) of each of the ferrite sintered magnets of Samples 1 to 34 were processed on the upper and lower surfaces of the cylindrical molded body, and then the maximum applied magnetic field of 25 kOe B Measurements were made at 25 ° C using a -H tracer. Here, Hk is the external magnetic field strength when the magnetic flux density is 90% of the residual magnetic flux density Br in the second quadrant of the obtained magnetic hysteresis loop. The obtained results are shown in Table 3.

Among the samples 1 to 34 described above, samples 1, 2, 3, and 34 fall outside the composition range of the present invention and therefore correspond to comparative examples, and the other samples correspond to examples of the present invention. Samples 1 and 2 have a composition in which the main phase does not contain Zn (y ″ z = 0), and samples 3 and 34 have a Si component content (in terms of SiO ₂ ) outside the scope of the present invention. Composition.

  And as shown in Table 3, all the samples of the examples had Br exceeding 4700 (G), whereas all the samples corresponding to the comparative examples had Br below 4700 (G). It was. In addition, each sample of the examples had HcJ sufficient for practical use exceeding 4000 (Oe).

Thus, according to the ferrite sintered magnet of the example, a Br value much higher than the conventional value exceeding 4700 (G) can be obtained while having a sufficient HcJ. Here, the value of 4700 (G) is an M-type ferrite sintered magnet having a composition represented by AFe ₁₂ O ₁₉ as in the present invention, and the element represented by A is Sr, and one of them. For the M-type ferrite in which a part is substituted with a rare earth element and a part of Fe is substituted with Co, the value is close to the theoretical value of Br expected so far. However, Br exceeding 4700 (G) is a value that could not be obtained practically due to characteristic deterioration due to insufficient orientation and sintering or contamination with impurities. Therefore, the fact that Br exceeding 4700 (G) is obtained as in the ferrite sintered magnet of the example means that the value of Br expected for the M-type ferrite sintered magnet has been sufficiently achieved. It is extremely useful.

[Samples 35-59]
In the method for manufacturing the ferrite sintered magnets of Samples 35 to 59, the following manufacturing methods D, E, or F were performed in addition to the manufacturing methods A and C described above.

(Production method D)
In the blending step, starting materials of La, Ca, Sr, Fe, Co and Zn were prepared, and these were weighed and used so that the composition of each element had the atomic ratio shown in Table 4.

In the pulverization step, La (OH) ₃ , CaCO ₃ , Fe ₂ O ₃ and SiO ₂ were added as post-additives during the second fine pulverization step. The amount of the post-additive was adjusted so that the composition of each element of the main phase and the content ratio of SiO ₂ were as shown in Table 5.

  This manufacturing method is an example in which a Co component and a Zn component, which are substitution elements for Fe sites, are added in the blending step.

(Manufacturing method E)
In the blending step, starting materials of La, Ca, Sr, Fe, Co and Zn were prepared, and these were weighed and used so that the composition of each element had the atomic ratio shown in Table 4.

In the pulverization step, La (OH) ₃ , CaCO ₃ , Fe ₂ O ₃ and SiO ₂ were added as post-additives during the second fine pulverization step. The amount of the post-additive was adjusted so that the composition of each element of the main phase and the content ratio of SiO ₂ were as shown in Table 5.

  This production method is also an example in which a Co component and a Zn component, which are Fe site substitution elements, are added in the blending step.

(Manufacturing method F)
In the blending step, starting materials of La, Ca, Sr and Fe were prepared, and these were weighed and used so that the composition of each element was the atomic ratio shown in Table 4.

In the pulverization step, La (OH) ₃ , CaCO ₃ , Fe ₂ O ₃ , Co ₃ O ₄ , ZnO and SiO ₂ were added as post-additives in the second fine pulverization step. The amount of the post-additive was adjusted so that the composition of each element of the main phase and the content ratio of SiO ₂ were as shown in Table 5.

  This manufacturing method is an example in which a Zn component and a Co component, which are Fe site substitution elements, are added in the pulverization step.

(composition)
In the manufacturing methods A, C, and D to F described above, the composition of the raw material compositions b1 to b10 prepared in the blending step is as shown in Table 4.

In addition, Table 5 shows the results of determining the composition of each of the ferrite sintered magnets of Samples 35 to 59 obtained above by quantitative fluorescent X-ray analysis. Table 5 also shows the raw material composition used in the production of each sample and the types of production methods (A, C, D to F).

(Evaluation of sintered ferrite magnet)
The magnetic properties (residual magnetic flux density Br, coercive force HcJ and squareness ratio Hk / HcJ) of each of the ferrite sintered magnets of Samples 35 to 59 were measured in the same manner as Sample 1 and the like. The results obtained are shown in Table 6.

Of the samples 35 to 59 described above, samples 35, 37, 38, 42, 46, 49, 53, 54, and 56 fall outside the composition range of the present invention, and thus fall under the comparative example. This corresponds to an embodiment of the invention. Samples 35 and 56 are comparative examples in which the atomic ratio of Co (y′z) and the total atomic ratio of Co and Zn (y′z + y ″ z) were outside the scope of the present invention. And 53 are comparative examples in which the atomic ratio (y ″ z) of Zn was outside the scope of the present invention, and Samples 38, 42, 46, 49 and 54 had a SiO ₂ content within the scope of the present invention. It is the comparative example which was outside.

  And as shown in Table 6, all the samples of the examples had Br exceeding 4700 (G) and HcJ sufficient for practical use exceeding 4000 (Oe). On the other hand, most of the samples corresponding to the comparative examples have Br less than 4700 (G), and HcJ is much less than 4000 (Oe) for Br exceeding 4700 (G). It was. From this, it was confirmed that each sample of the sintered ferrite magnet of the example had a high Br while maintaining a high HcJ as compared with the conventional sample.

  Further, among the samples of the examples, even if the sample obtained by the manufacturing method D and the sample obtained by the manufacturing method F were compared, the values of Br and HcJ did not change greatly. It has been found that the effect of improving the magnetic properties (particularly Br) can be sufficiently obtained even when added in the blending step or in the grinding step.

[Samples 60 to 84]
In manufacturing the sintered ferrite magnets of Samples 60 to 84, the following manufacturing method G, H, or I was performed.

(Manufacturing method G)
In the blending process, starting materials of La, Ca, Sr and Co were prepared, and these were weighed and used so that the composition of each element would be the atomic ratio shown in Table 7.

In the pulverization step, La (OH) ₃ , ZnO, CaCO ₃ , Fe ₂ O ₃ and SiO ₂ were added as post-additives during the second fine pulverization step. The amount of the post-additive was adjusted so that the composition of each element of the main phase and the content ratio of SiO ₂ were as shown in Table 8.

  This manufacturing method is an example in which the Co component is added in the blending step and the Zn component is added in the pulverization step among the substitution elements of the Fe site.

(Manufacturing method H)
In the blending step, starting materials of La, Ca, Sr, Co and Zn were prepared, and these were weighed and used so that the composition of each element had the atomic ratio shown in Table 7.

In the pulverization step, La (OH) ₃ , CaCO ₃ , Fe ₂ O ₃ and SiO ₂ were added as post-additives during the second fine pulverization step. The amount of the post-additive was adjusted so that the composition of each element of the main phase and the content ratio of SiO ₂ were as shown in Table 8.

  This manufacturing method is an example in which both the Co component and the Zn component are added in the blending step among the substitution elements at the Fe site.

(Production Method I)
In the blending step, starting materials for La, Ca, Sr and Fe were prepared, and these were weighed and used so that the composition of each element would be the atomic ratio shown in Table 7.

In the pulverization step, Co ₃ O ₄ , ZnO, CaCO ₃ , Fe ₂ O ₃ and SiO ₂ were added as post-additives in the second fine pulverization step. The amount of the post-additive was adjusted so that the composition of each element of the main phase and the content ratio of SiO ₂ were as shown in Table 8.

  This manufacturing method is an example in which both the Co component and the Zn component are added in the pulverization step among the substitution elements at the Fe site.

(composition)
In the manufacturing methods G, H and I described above, the composition of the raw material compositions c1 to c19 prepared in the blending step is as shown in Table 7.

Table 8 shows the results of determining the composition of each of the ferrite sintered magnets of Samples 60 to 84 obtained above by fluorescent X-ray quantitative analysis. Table 8 also shows the raw material composition used in the production of each sample and the type (G, H or I) of the production method.

(Evaluation of sintered ferrite magnet)
The magnetic characteristics (residual magnetic flux density Br, coercive force HcJ and squareness ratio Hk / HcJ) of each ferrite sintered magnet of Samples 60 to 84 were measured in the same manner as Sample 1 and the like. Table 9 shows the obtained results.

  Among the samples 60 to 84 described above, the samples 65 and 78 fall outside the composition range of the present invention and therefore correspond to comparative examples, and the other samples correspond to the examples of the present invention. The sample of the comparative example has a value of 12z (total atomic ratio of Fe sites) outside the scope of the present invention.

  And as shown in Table 9, all of the samples of the examples had Br exceeding 4700 (G) and HcJ sufficient for practical use exceeding 4000 (Oe). On the other hand, the sample corresponding to the comparative example had Br lower than 4700 (G), or HcJ was significantly lower than 4000 (Oe). From this, it was confirmed that each sample of the sintered ferrite magnet of the example had a high Br while maintaining a high HcJ as compared with the conventional sample.

  Further, among the samples of the examples, the samples obtained by the production methods G, H, or I did not greatly change the values of Br and HcJ, so that Zn and Co were used in the blending process and the pulverization process. It has been found that the effect of improving the magnetic properties (particularly Br) can be sufficiently obtained even if they are added separately or simultaneously in these steps.

[Samples 85-122]
In the production of the ferrite sintered magnets of Samples 85 to 122, the following production methods J and K were performed in addition to the production method A described above.

(Manufacturing method J)
In the blending step, starting materials of La, Ca, Sr, Fe and Co were prepared, and these were weighed and used so that the composition of each element would be the atomic ratio shown in Table 10.

In the pulverization step, La (OH) ₃ , ZnO, CaCO ₃ , Fe ₂ O ₃ and SiO ₂ were added as post-additives during the second fine pulverization step. The amount of the post-additive was adjusted so that the composition of each element of the main phase and the content ratio of SiO ₂ were as shown in Table 11.

  This manufacturing method is an example in which the Co component is added in the blending step and the Zn component is added in the pulverizing step among the substitution elements of Fe sites.

(Manufacturing method K)
In the blending step, starting materials of La, Ca, Sr, Fe, Co, and Zn were prepared, and these were weighed and used so that the composition of each element had the atomic ratio shown in Table 10.

In the pulverization step, CaCO ₃ and SiO ₂ were added as post-additives during the second fine pulverization step. The amount of the post-additive was adjusted so that the composition of each element of the main phase and the content ratio of SiO ₂ were as shown in Table 11.

  This manufacturing method is an example in which both the Co component and the Zn component among the substitution elements of the Fe site are added in the blending step.

(composition)
In the manufacturing methods J and K described above, the compositions of the raw material compositions d1 to d38 prepared in the blending step are as shown in Table 10.

Table 11 shows the results of determining the composition of each of the ferrite sintered magnets of Samples 85 to 122 obtained above by fluorescent X-ray quantitative analysis. Table 11 also shows the raw material composition used in the production of each sample and the type (J or K) of the production method.

(Evaluation of sintered ferrite magnet)
The magnetic properties (residual magnetic flux density Br, coercive force HcJ and squareness ratio Hk / HcJ) of each of the ferrite sintered magnets of Samples 85 to 122 were measured in the same manner as Sample 1 and the like. The results obtained are shown in Table 12.

  Among the samples 85 to 122 described above, the samples 85, 88, 118, and 122 fall outside the composition range of the present invention and thus correspond to comparative examples, and the other samples correspond to the examples of the present invention. Samples 85 and 122 are comparative examples in which the atomic ratio of Ca was outside the scope of the present invention, and samples 88 and 118 were comparative examples in which the atomic ratio of La was outside the scope of the present invention.

  And as shown in Table 12, all the samples of the examples had Br exceeding 4700 (G) and HcJ sufficient for practical use exceeding 4000 (Oe). On the other hand, most of the samples corresponding to the comparative examples have Br less than 4700 (G), and HcJ is much less than 4000 (Oe) for Br exceeding 4700 (G). It was. From this, it was confirmed that each sample of the sintered ferrite magnet of the example had a high Br while maintaining a high HcJ as compared with the conventional sample.

[Samples 123-135]
In manufacturing the ferrite sintered magnets of Samples 123 to 135, the following manufacturing method L, M, N, or O was performed.

(Manufacturing method L)
In the blending process, starting materials of La, Ca, Sr, Ba, Fe and Co were prepared, and these were weighed and used so that the composition of each element had the atomic ratio shown in Table 13.

In the pulverization step, CaCO ₃ and SiO ₂ were added as post-additives during the second fine pulverization step. The amount of the post-additive was adjusted so that the composition of each element of the main phase and the content ratio of SiO ₂ were as shown in Table 14.

  This manufacturing method is an example in which, in addition to the Sr component as a starting material for the A element, the Ba component is added in the blending step, and the Zn component is not added among the substitution elements at the Fe site.

(Manufacturing method M)
In the blending process, starting materials of La, Ca, Sr, Ba, Fe and Co were prepared, and these were weighed and used so that the composition of each element had the atomic ratio shown in Table 13.

In the pulverization step, La (OH) ₃ , ZnO, Fe ₂ O ₃ , CaCO ₃ and SiO ₂ were added as post-additives during the second fine pulverization step. The amount of the post-additive was adjusted so that the composition of each element of the main phase and the content ratio of SiO ₂ were as shown in Table 14.

  In this manufacturing method, the Ba component is added in the blending step in addition to the Sr component as the starting material for the element A, the Co component is added in the blending step, and the Zn component is added in the pulverizing step. It is an example.

(Manufacturing method N)
In the blending step, starting materials of La, Ca, Sr, Ba, Fe, Co and Zn were prepared, and these were weighed and used so that the composition of each element had the atomic ratio shown in Table 13.

In the pulverization step, CaCO ₃ and SiO ₂ were added as post-additives during the second fine pulverization step. The amount of the post-additive was adjusted so that the composition of each element of the main phase and the content ratio of SiO ₂ were as shown in Table 14.

  This manufacturing method is an example in which, in addition to the Sr component, the Ba component is added in the blending step as a starting material for the A element, and both the Co component and the Zn component of the Fe site substitution elements are added in the blending step. .

(Manufacturing method O)
In the blending step, starting materials of La, Ca, Sr, Ba, and Fe were prepared, and these were weighed and used so that the composition of each element had the atomic ratio shown in Table 13.

In the pulverization step, Co ₃ O ₄ , ZnO, Fe ₂ O ₃ , CaCO ₃ and SiO ₂ were added as post-additives during the second fine pulverization step. The amount of the post-additive was adjusted so that the composition of each element of the main phase and the content ratio of SiO ₂ were as shown in Table 14.

  This manufacturing method is an example in which a Ba component is added as a starting material for the A element in the blending step in addition to the Sr component, and both the Co component and the Zn component, which are Fe site substitution elements, are added in the grinding step. .

(composition)
In the manufacturing methods L to O described above, the compositions of the raw material compositions e1 to e6 prepared in the blending step are as shown in Table 13.

In addition, Table 14 shows the results of determining the composition of each of the ferrite sintered magnets of Samples 123 to 135 obtained above by fluorescent X-ray quantitative analysis. Table 14 also shows the raw material composition used in the production of each sample and the type (L to O) of the production method.

(Evaluation of sintered ferrite magnet)
The magnetic properties (residual magnetic flux density Br, coercive force HcJ, and squareness ratio Hk / HcJ) of the ferrite sintered magnets of Samples 123 to 135 were measured in the same manner as Sample 1 and the like. The results obtained are shown in Table 15.

Among the samples 123 to 135 described above, the samples 123, 124, and 129 fall outside the composition range of the present invention and therefore correspond to comparative examples, and the other samples correspond to the examples of the present invention. Incidentally, the sample of the comparative example, both the content of SiO ₂ are comparative examples were outside the scope of the present invention.

  And as shown in Table 15, all of the samples of the examples had Br exceeding 4700 (G) and HcJ sufficient for practical use exceeding 4000 (Oe). On the other hand, the samples corresponding to the comparative examples all had Br lower than 4700 (G), and some HcJ was significantly lower than 4000 (Oe). From this, it was confirmed that each sample of the sintered ferrite magnet of the example had a high Br while maintaining a high HcJ as compared with the conventional sample.

It is a model perspective view which shows an example of the shape of a ferrite sintered magnet.

Explanation of symbols

  10: Ferrite sintered magnet.

Claims (1)

A ferrite sintered magnet in which a ferrite phase having a hexagonal crystal structure forms a main phase,
The composition of the metal element constituting the ferrite sintered magnet is represented by the following general formula (1):
_{R x Ca m A 1-x} -m (Fe 12-y'y '' Co y 'Zn y'') z ... (1)
(In the formula (1), R represents one or more elements selected from the group consisting of La, Ce, Pr, Nd and Sm containing La as an essential component, and A represents from Sr and Ba containing Sr as an essential component. Indicates at least one element selected.)
In the formula (1), x, m, y ′, y ″ and z are represented by the following formulas (2), (3), (4), (5), (6) and (7). Satisfy all the conditions,
0.23 ≦ x ≦ 0.5 (2)
0.12 ≦ m ≦ 0.39 (3)
0.17 ≦ y′z ≦ 0.36 (4)
0.01 ≦ y ″ z ≦ 0.11 (5)
0.19 ≦ y′z + y ″ z ≦ 0.40 (6)
9.8 ≦ 12z ≦ 11.7 (7)
And, as a sub-component, containing 0.13 to 0.48 wt% in terms of Si component in SiO _2,
A ferrite sintered magnet characterized by that.

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