JP4438445B2 - Rare earth hybrid bonded magnet composition and rare earth hybrid bonded magnet - Google Patents

Description

  The present invention relates to a composition for a rare earth hybrid bonded magnet and a rare earth hybrid bonded magnet. More specifically, the weather resistance is improved by reducing the chlorine content, and the magnet is demagnetized and rusted even in a high humidity environment. The present invention relates to a rare earth hybrid bonded magnet composition and a rare earth hybrid bonded magnet.

  Permanent magnets are parts that have various fields of use ranging from miscellaneous goods to motors and sensors. The types are classified by materials, such as ferrite, rare earth magnetic materials such as Sm-Co and Nd-Fe-B, and metal magnetic materials such as alnico and iron-chromium-cobalt. On the other hand, when classified according to the magnet manufacturing method, there are a sintered magnet using a powder metallurgy technique, a bonded magnet made of magnetic powder and a resin binder, and a cast magnet.

  Bond magnets are classified into injection-molded magnets, extrusion-molded magnets, compression-molded magnets, rolled-molded magnets, etc., depending on the molding method. In addition, when magnetizing a magnet to N pole and S pole, an isotropic magnet that can be magnetized in an arbitrary direction by magnetization, and an anisotropic magnet that is used by being magnetized in a certain direction determined when the magnet is manufactured, It can also be classified.

  Sintered magnets can densify the magnetic powder to a relative density of 90% or more by a metallurgical technique, so that the magnetic force of the material can be extracted as it is, but have the disadvantage that the degree of freedom in shape is small and the mechanical strength is poor. On the other hand, the bonded magnet is made of a resin powder made of magnetic powder, so the magnetic force is weakened only by the resin volume, but it has excellent shape flexibility and mechanical strength and can be integrally molded with other parts. It has features such as being. Therefore, they are used in applications that take advantage of their characteristics.

The magnetic properties of the permanent magnet can be selected widely depending on the combination of the above materials and the manufacturing method. For example, a ferrite bonded magnet can be selected up to a maximum energy product of 16 kJ / m ^3, and a ferrite sintered magnet can be selected up to about 36 kJ / m ³ .

These ferrite magnets are widely used because the ferrite magnetic powder of the material is inexpensive, but rare earth magnetic materials more expensive than ferrite may be used when magnetic properties higher than 36 kJ / m ³ are required. Many. For example, up to about 95 kJ / m ³ can use Sm—Co based or Nd—Fe—B based bonded magnets, and up to 430 kJ / m ³ from Sm—Co based or Nd—Fe—B based sintered magnets. You can choose.

Further, the magnetic characteristic area of the maximum energy product of greater than ferrite bond magnet until 16 kJ / m ³ or more 100 kJ / m about ^3, can be arbitrarily adjusted magnetic properties, and a ferrite utilizing the low cost Bond magnets mixed with rare earth magnetic materials, that is, hybrid bond magnets have been developed.

  As an example of this, a hybrid bond magnet (see Patent Document 1) in which an anisotropic manganese-aluminum-carbon-based magnet alloy powder is the main component and a ferrite magnet fine powder and a rare earth cobalt magnet fine powder are mixed with this, and ferrite Hybrid bond magnets (see Patent Documents 2 and 3) in which magnet powder and rare earth cobalt magnet powder are mixed have been proposed.

  Further, a hybrid bond magnet composed of ferrite magnetic powder and Nd—Fe—B based magnetic powder (see Patent Documents 4 to 6), and a hybrid bond magnet composed of ferrite magnetic powder and Sm—Fe—N based magnetic powder (Patent Document). 7 and 8) have been proposed.

  However, conventional hybrid bond magnets using Sm—Co based magnetic powder or Nd—Fe—B based magnetic powder do not provide desired magnetic properties unless the amount of rare earth magnetic powder is increased, and cost cannot be reduced. It was. This is because the magnetization of the magnetic powder is small in the Sm—Co system, and the magnetic powder is isotropic and the magnetization is not sufficiently large in the Nd—Fe—B system.

  In recent years, rare earth hybrid bonded magnets manufactured from a composition in which the above ferrite magnetic fine powder and rare earth cobalt magnet fine powder are mixed with a resin are often used in applications exposed to high humidity environments. In such a case, in the rare earth hybrid bonded magnet, the magnet is demagnetized and rust is generated, causing a serious problem in terms of weather resistance.

  This problem can also occur in bonded magnets that contain only rare earth magnetic powders that do not contain ferrite magnetic powder. However, with such bonded magnets, a protective layer such as a coating or skin layer may be provided on the surface of the magnet, It could be avoided by applying an appropriate surface treatment.

  The weather resistance of hybrid bonded magnets is also improved in the same way, but the effect of the protective layer and surface treatment is small compared to rare earth bonded magnets, and the demagnetization and rusting of the magnets could not be sufficiently prevented. (For example, refer to Patent Document 10).

  By the way, in Nd-Fe-B type rare earth bonded magnets, it is disclosed that it is important to improve the corrosion resistance by setting the chlorine concentration in the resin binder to 200 ppm or less (Patent Document 9). Here, rust can be suppressed by reducing the amount of chlorine as much as possible. However, ferrite magnetic powder is not included as a component, and only a resin binder is considered as a chlorine supply source.

Even hybrid bond magnets using Sm-Fe-N-based magnetic powder are still not sufficient in terms of weather resistance, and their magnetic properties deteriorate when left in a high temperature or high humidity environment for a long time. The problem to do was pointed out.
JP-A-55-99703 JP-A-57-39102 JP-A-60-223095 Japanese Patent Laid-Open No. 61-284906 JP 62-257703 A JP 09-092515 A JP 2000-021615 A JP 2000-124018 A Japanese Patent Laid-Open No. 07-122416 JP 2002-110410 A

  In view of the above-mentioned problems of the prior art, the object of the present invention is to improve the weather resistance by reducing the chlorine content, and rare earth hybrid bonds that are less susceptible to magnet demagnetization and rust even in high humidity environments. It is in providing the composition for magnets and a rare earth hybrid bond magnet.

  As a result of intensive studies to solve the above problems, the present inventors have studied the effect of chlorine content on weather resistance when adding ferrite magnetic powder to rare earth magnetic powder, If the residual soluble chlorine content is less than or equal to a predetermined amount and the residual chlorine content in the entire composition for rare earth hybrid bonded magnets is less than or equal to a predetermined amount, the rare earth rarely generates magnet demagnetization and rust even in a high humidity environment. A hybrid bonded magnet can be obtained, and furthermore, it has been found that selecting a ferrite magnetic powder having a small average particle size or a rounded shape with few corners can provide a greater effect, and the present invention has been completed. It was.

That is, according to the first aspect of the present invention, a rare earth hybrid mainly composed of a rare earth magnetic powder (A) , a ferrite magnetic powder (B) selected from Sr ferrite or Ba ferrite , and a resin binder (C). In the bonded magnet composition, the residual soluble chlorine content of the ferrite magnetic powder (B) is 30 to 300 ppm, the residual chlorine content of the entire composition is 150 ppm or less, and the average particle size of the ferrite magnetic powder (B) When the diameter is 3 μm or less and exceeds 1 μm, a rare earth hybrid bonded magnet composition is provided that satisfies the relational expression represented by the following formula .
A / (6 / (ρ × B)) <2
[In the formula, A represents the BET specific surface area (m ² / g) of the ferrite magnetic powder, ρ represents the true density (Mg / m ³ ) of the ferrite magnetic powder, and B represents the average particle diameter (m) of the ferrite magnetic powder]

  According to a second aspect of the present invention, in the first aspect, the rare earth-based magnetic powder (A) is a rare earth-based magnetic powder mainly comprising a rare earth element, iron or iron and cobalt, and nitrogen or boron. A composition for rare earth hybrid bonded magnets is provided.

According to a third aspect of the present invention, there is provided the rare earth hybrid bonded magnet according to the first aspect, wherein the proportion of the ferrite magnetic powder (B) is 20 to 70% by weight based on the entire composition. A composition is provided.

Furthermore, the fourth invention of the present invention is the composition for a rare earth hybrid bonded magnet according to the first invention, wherein the resin binder (C) is a polyamide resin and the amount of residual soluble chlorine is 100 ppm or less. Things are provided.

On the other hand, in the fifth invention of the present invention, the rare earth hybrid bonded magnet composition according to any one of the first to fourth inventions is selected from an injection molding method, a compression molding method, an extrusion molding method, or a rolling molding method. There is provided a rare earth hybrid bonded magnet formed by at least one forming method.

The sixth invention of the present invention is characterized in that, in the fifth invention, the permanent demagnetization factor when left in a high temperature and high humidity environment of 95 ° C. and 95% RH for 300 hours is less than −5%. A rare earth hybrid bonded magnet is provided.

  The composition for rare earth hybrid bonded magnets based on the rare earth magnetic powder and ferrite magnetic powder of the present invention has a limited amount of residual chlorine in the entire composition, and the ferrite magnetic powder has a very small amount of residual soluble chlorine. Therefore, the resulting rare earth hybrid bonded magnet is greatly improved in weather resistance under a high humidity environment. In particular, by using a ferrite magnetic powder as a raw material having a small average particle diameter or a smooth surface property with a rounded corner, a rare earth hybrid bonded magnet with further improved weather resistance can be obtained.

  The composition for rare earth hybrid magnet of the present invention and the rare earth hybrid magnet using the composition will be described in detail below.

1. Rare earth magnetic powder (A)
In the present invention, the rare earth-based magnetic powder includes R-Fe-N-based magnetic powder mainly composed of rare earth elements, iron or iron and cobalt, and nitrogen, or rare earth elements, iron, iron and cobalt, and boron. And R—Fe—B based magnetic powders mainly composed of

The R—Fe—N based magnetic powder is a Th ₂ Zn ₁₇ type mainly composed of rare earth elements (R), iron (Fe) or iron (Fe), cobalt (Co), and nitrogen (N), Th ₂ Magnetic powder having a Ni ₁₇ type or TbCu ₇ type crystal structure.

  R-Fe-N-based magnetic powders are disclosed in, for example, JP-A-2-57663, JP-A-3-16102, JP-A-3-101102, JP-A-3-141608, and JP-A-3-153852. JP-A-3-160705, JP-A-4-288801, JP-A-7-066021, JP-A-8-45718, JP-A-8-55712, JP-A-8-144024, JP-A-8-316018, JP-A-10-163056, JP-A-10-241923, JP-A-10-289811, JP-A-11-293418, JP-A-11-297518, JP This is disclosed in Japanese Patent Laid-Open No. 2001-313206.

  As a method for producing the R—Fe—N magnetic powder, as described in these patent documents, rare earth-iron (Fe) or rare earth-iron (Fe) cobalt (Co) alloy not containing nitrogen is used. Examples thereof include a method in which powder is produced by a reduction diffusion method, a dissolution casting method, a liquid quenching method, and the like, and then nitrogen is introduced into the alloy powder by heat treatment in an atmosphere containing nitrogen or nitrogen atoms.

Since rare earth hybrid bonded magnets are often required to reduce costs, in the present invention, it is desirable to manufacture a raw material alloy powder by a reduction diffusion method having a low manufacturing cost.
The production of magnetic powder by the reduction diffusion method is described in JP-A-5-148517 and JP-A-9-143636.
The composition of the obtained magnetic powder is as follows: R (R is a rare earth element and Sm is contained in 80 wt% or more) 20 to 25 wt%, N is 2.1 to 5.3 wt%, and the balance is T (T is Fe, Or Fe and Co). In addition, 7 wt% or less of one or more of Ti, V, Cr, Mn, Ni, Cu, Zr, Nb, Mo, Ag, Hf, Ta, W, Re, Os, Ir, Pt, and Au is added to the main component. Then, heat resistance can be improved.

  In order to produce a rare earth-iron-based mother alloy powder by this reduction diffusion method, (1) a reducing agent is mixed with a raw material powder such as an oxide containing rare earth elements and iron powder, and (2) this mixture is heated to a specific temperature. And the rare earth element is reduced and diffused into the iron-based alloy, (3) the obtained reaction product is disintegrated, and (4) the disintegrated powder is produced by wet treatment.

(1) Preparation of raw material powder The rare earth oxide powder used in the present invention includes at least one element selected from Sm, Gd, Tb, and Ce, or Pr, Nd, Dy, Ho, Er, Tm. And those containing at least one element selected from Yb. Among these, those containing Sm are particularly preferable because the effects of the present invention can be remarkably exhibited. In the case where Sm is contained, in order to obtain a high coercive force, Sm needs to be 50% by weight or more, preferably 90% by weight or more of the entire rare earth.

  If an appropriate amount of iron powder is replaced with iron oxide powder, a uniform reduction diffusion reaction can be realized by utilizing the exothermic reaction during the reduction. Furthermore, the raw material powder includes Ti, V, Cr, Mn, Ni, Cu, Zr, Nb, Mo, Ag, Hf, Ta, W for improved coercive force, improved productivity, and lower cost. , Re, Os, Ir, Pt, Au and the like may be added, but the amount added is preferably 7% by weight or less in total. Further, as an inevitable impurity, C or the like may be contained in an amount of 5% by weight or less.

(2) Reduction diffusion Next, the raw material powder and the reducing agent are put into a reaction vessel and heat-treated under specific conditions to reduce the rare earth oxide and other oxide raw materials and diffuse them into the iron powder. Thus, a rare earth-iron master alloy is produced.

  The reducing agent is selected from alkali metals, alkaline earth metals, and hydrides thereof, and calcium metal is preferred in terms of handling safety and cost. The reducing agent can be mixed with the raw material powder or separated so that calcium vapor can come into contact with the raw material powder. When separated, uniform nitriding is promoted, and the squareness of the obtained magnet powder can be improved.

  It is also effective to mix with the raw material powder an additive that promotes the decay of the reaction product in the subsequent wet processing step. As the disintegration accelerator, alkaline earth metal salts such as calcium chloride, calcium oxide and the like can be used, and they are uniformly mixed simultaneously with the raw material powder.

  It is important that the raw material powders are mixed uniformly so as not to separate due to differences in powder characteristics. As a mixing method, for example, a ribbon blender, a tumbler, an S-shaped blender, a V-shaped blender, a Nauter mixer, a Henschel mixer, a super mixer, a high speed mixer, a ball mill, a vibration mill, an attritor, a jet mill and the like can be used.

  The reduction temperature is desirably in the range of 1090 to 1250 ° C, particularly 1100 to 1230 ° C. If it is less than 1090 ° C., the diffusion of rare earth elements and the like becomes non-uniform with respect to the iron powder, and the coercive force and squareness of the obtained rare earth-iron-nitrogen based magnet powder are lowered. When the temperature exceeds 1250 ° C., the generated rare earth-iron mother alloy undergoes grain growth and sinters with each other. Therefore, uniform nitriding becomes difficult, and the squareness of the magnet powder decreases.

(3) Hydrogen treatment When a reduction diffusion reaction is performed using calcium as a reducing agent, the obtained rare earth-iron-based master alloy becomes a massive mixture composed of calcium oxide, unreacted excess metallic calcium, and the like. For example, the reaction product may be treated with hydrogen to disrupt the mixture.

  The hydrogen treatment is performed at a temperature of 500 ° C. or less, but it is necessary to set the reaction temperature and time so that the particle size of the taken-out collapsed product is 10 mm or less, preferably 1 mm or less. In the state where the collapsed material exceeds 10 mm, uniform nitriding becomes difficult in the nitriding treatment step performed subsequent to the wet treatment, and the squareness of the magnet powder is lowered.

(4) Wet treatment The reaction product obtained as described above is subjected to a wet treatment to separate and remove by-products (residual impurities) caused by a reducing agent component such as calcium oxide from the rare earth-iron master alloy.

In the wet treatment, first, the disintegrated product is put into water, and decantation-water injection-decantation is repeated to remove much of Ca (OH) ₂ . In order to remove residual Ca (OH) ₂ , acid washing is performed using acetic acid and / or hydrochloric acid. At this time, the hydrogen ion concentration (pH) of the aqueous solution is preferably in the range of 4-6.
After the completion of such treatment, it is washed with water, dehydrated with an organic solvent such as alcohol or acetone, and dried in an inert gas atmosphere or vacuum to obtain a rare earth-iron-based mother alloy powder.

  In the present invention, the rare earth-iron-nitrogen based magnet powder is the above rare earth-iron based mother alloy powder specified in a mixed gas stream composed of ammonia and hydrogen whose ratio of the partial pressure of ammonia to the total gas pressure is in a specific range. It is manufactured by nitriding by heat treatment at temperature.

  The rare earth-iron-based mother alloy powder has a ratio of ammonia partial pressure to total air flow pressure of 0.2 to 0.8, preferably 0.3 to 0.6. A nitriding heat treatment is performed at 550 ° C., preferably 410 to 510 ° C.

  Here, if the ratio of the ammonia partial pressure to the total air flow pressure is less than 0.2, nitridation does not proceed over a long period of time, and if the ammonia partial pressure ratio exceeds 0.8, The nitrogen composition does not become uniform near the center, the amorphous phase increases especially near the surface, and the magnetization and squareness of the magnet powder decrease.

  If the heating temperature is less than 400 ° C., nitriding is difficult to proceed. If the heating temperature is too low or the heating time is too short, an unnitrided phase will remain inside the powder. Conversely, if the temperature is too high or the heating time is too long, it will be overnitrided, and the magnet powder's magnetization, coercive force, squareness will be Therefore, the processing conditions are optimized as appropriate. As the heating device, a stationary heating furnace, a fluidized bed heating furnace, a rotary heating furnace, etc. can be used. In order to make the contact between the alloy fine powder and the gas uniform, the powder is stirred. However, nitriding may be performed.

  As the R—Fe—B magnetic powder, an isotropic or anisotropic Nd—Fe—B magnetic powder produced by a liquid quenching method or an R—Fe—B magnetic alloy is heat-treated in a hydrogen atmosphere. An isotropic or anisotropic Nd—Fe—B magnetic powder produced by the HDDR method or the d-HDDR method can be used.

  These R—Fe—N and R—Fe—B magnetic powders are preferably used as fine powders having an average particle diameter of 1 to 10 μm. If the average particle size is less than 1 μm, it is difficult to handle the magnet powder industrially, and if it exceeds 10 μm, uniform mixing with the ferrite magnetic powder becomes difficult.

The fine powder having an average particle size of 1 to 10 μm can be formed on the surface of the magnetic powder with a gradual oxide film by wet or dry treatment in order to improve handling properties such as prevention of ignition.
This film forming method is disclosed in, for example, JP-A-52-54998, JP-A-59-170201, JP-A-60-128202, JP-A-3-21203, JP-A-46-7153. JP-A-56-55503, JP-A-61-154112, and JP-A-3-126801. However, for the isotropic or anisotropic R-Fe-B magnetic powder produced by the HDDR method or the d-HDDR method, the magnetic properties are reduced when the particle size is reduced. It may not be desirable.

  JP-A-4-338603, JP-A-5-230501, JP-A-5-234729, JP-A-8-143913, JP-A-7-268632, JP-A-9-190909, etc. No. 6-17015, JP-A-1-234502, JP-A-4-21702, JP-A-5-213601, and JP-A-7. -326508, JP-A-8-153613, JP-A-8-183601, JP-2002-124406, JP-2002-359107, JP-2003-007521, etc. You can also use the method to do. When one or more kinds of these surface treatments are applied to the R—Fe—N or R—Fe—B based magnetic powder, the heat resistance of the rare earth hybrid magnet is improved.

2. Ferrite magnetic powder (B)
The ferrite magnetic powder (B) used in the present invention plays an important role in maintaining good squareness of the rare earth hybrid magnet.

  The ferrite magnetic powder may be either Sr ferrite or Ba ferrite, but Sr ferrite is preferable in order to improve squareness.

  The amount of soluble chlorine remaining in the ferrite magnetic powder and the surface properties of the powder are important in order to obtain a composition and magnet for a rare earth hybrid bond magnet in which magnet demagnetization and rust are unlikely to occur even in a high humidity environment. The residual soluble chlorine content of the ferrite magnetic powder is the amount of chlorine detected by ion chromatography analysis of a solution obtained by extracting the powder with pure water of hot water (80 ° C.).

  In Nd—Fe—B based rare earth bonded magnets, it is said that regulating the chlorine content in the resin binder to 200 ppm or less is important for improving the corrosion resistance (Patent Document 9). Even in the R—Fe—B rare earth hybrid bond magnet, rust can be suppressed by reducing the chlorine content as much as possible. In this case, as a chlorine supply source, a ferrite magnetic powder is used rather than a resin binder. is important.

When producing a ferrite magnetic powder, iron oxide generally obtained from iron chloride is generally used as a starting material, and the ferrite magnetic powder is usually washed so that the amount of residual soluble chlorine is 1000 ppm or less ( JP, 2002-353019, A).
However, the soluble chlorine remaining in the treated ferrite magnetic powder cannot be completely removed, and the residual chlorine generates rust in the R—Fe—B rare earth hybrid bond magnet in a high humidity environment. There are many cases. However, in the R—Fe—N rare earth hybrid bond magnet, the amount of chlorine affects demagnetization in a high humidity environment, but unlike the R—Fe—B system, almost no rust is generated. Since it is not seen, the mechanism of action is assumed to be different.

  As described above, in any rare earth hybrid bonded magnet, it is important to regulate the amount of chlorine from the viewpoint of weather resistance, but as a ferrite magnetic powder used in the hybrid bonded magnet, it is sufficiently cost effective and quality However, it must use iron chloride-based iron oxide as a starting material.

  If the amount of residual soluble chlorine in the ferrite magnetic powder is 30 to 300 ppm, a rare earth hybrid bond magnet having good weather resistance can be produced. When it exceeds 300 ppm, the weather resistance of the rare earth hybrid bonded magnet composition or the magnet is lowered. From the viewpoint of weather resistance, it is preferable to reduce the amount of residual soluble chlorine as much as possible, but in order to make it less than 30 ppm, a step of reducing the amount of residual soluble chlorine to the limit is required, and the cost of the ferrite magnetic powder increases. Alternatively, there may be cases where sufficient magnetic properties cannot be obtained due to the influence of the additional process.

  By the way, the problem of demagnetization and rust caused by residual chlorine is alleviated by applying an appropriate surface treatment to the rare earth magnetic powder, but it is not sufficient. The problem of demagnetization and rust is affected by the surface properties of the ferrite magnetic powder, especially in the case of the ferrite magnetic powder having an angular shape, and the demagnetization and rust are worsened. Rust hardly occurs.

  If the ferrite magnetic powder having an angular shape is used, the ferrite magnetic powder having an angular shape is formed in the process of mixing and kneading the resin binder and the magnetic powder or forming the composition into a magnet during the manufacturing process of the rare earth hybrid bond magnet. It is presumed that the surface of the rare earth magnetic powder is damaged, and as a result, the surface coating is destroyed.

  Therefore, in order to solve the above problem, a fine ferrite magnetic powder that does not easily damage the surface of the rare earth magnetic powder may be used, or a ferrite magnetic powder having a round surface may be used.

The average particle size B of the ferrite magnetic powder is not particularly limited, but is preferably 1 × 10 ⁻⁵ m (10 μm) or less, preferably 5 μm or less, and more preferably 3 μm or less.
When the average particle size exceeds 1 × 10 ⁻⁵ m, the coercive force of the ferrite magnetic powder is lowered, and the squareness of the hybrid bond magnet is lowered. In addition, the proportion of the magnetic powder composed of rare earth magnetic powder and ferrite magnetic powder in the resin binder cannot be increased, or even if it is increased, the fluidity of the composition for rare earth hybrid magnets decreases and magnet formation becomes impossible. Or the orientation performance, which is an important element as an anisotropic magnet, deteriorates and the magnetic characteristics deteriorate.
The true density ρ of the ferrite magnetic powder is preferably 4.6 to 5.2 Mg / m ³ .

In the present invention, only when the average particle diameter of the ferrite magnetic powder (B) is 1 to 10 μm, the following formula: A / (6 / (ρ × B)) <2
[In the formula, A represents the BET specific surface area (m ² / g) of the ferrite magnetic powder, ρ represents the true density (Mg / m ³ ) of the ferrite magnetic powder, and B represents the average particle diameter (m) of the ferrite magnetic powder] The relational expression expressed by

Here, 6 / (ρ × B) indicated in the denominator on the left side of the inequality sign is the specific surface area of the spherical powder having a single particle diameter of the diameter B (m). The ratio of the specific surface area of this spherical powder to the BET specific surface area A, A / (6 / (ρ × B)) takes a value greater than 1, and the value increases as the powder becomes angular and deviates from the true sphere, resulting in more irregularities. When the number is 2 or more, the surface becomes extremely uneven, and the permanent demagnetization rate of the hybrid bond magnet increases. This is presumably because the ferrite magnetic powder damages the surface of the rare earth magnetic powder during kneading of the bonded magnet composition or molding of the bonded magnet.
In the relationship between the surface state of the rare earth hybrid bond magnet and the magnetic properties (permanent demagnetization factor), the above inequality is established regardless of the constituent ratio of the ferrite magnetic powder.

  Therefore, in a ferrite magnetic powder having a relatively large particle size, good moisture resistance can be obtained by using a rounded ferrite magnetic powder that satisfies this condition. Moreover, if A / (6 / (ρ × B)) is set small within this range, the magnetic properties (permanent demagnetization factor) of the rare earth hybrid bond magnet can be reduced, and the generation of rust can be suppressed. It becomes possible.

The BET specific surface area of the ferrite magnetic powder is not particularly limited, but is usually 1.5 m ² / g or more, preferably 2.0 m ² / g or more, more preferably 3.5 m while maintaining the above powder properties. ² / g or more. When the specific surface area is less than 1.5 m ² / g, the squareness is deteriorated.

  The magnetic properties of the ferrite magnetic powder are preferably such that the coercive force is 310 kA / m or more. Ferrite magnetic powder receives a shearing force in the manufacturing process of the rare earth hybrid magnet, and the coercive force is greatly reduced by strain. Therefore, if the coercive force of the ferrite magnetic powder is less than 310 kA / m, a rare earth hybrid bonded magnet having excellent squareness cannot be obtained.

The bulk density of the mixed powder of rare earth magnetic powder and ferrite magnetic powder is preferably 2.3 g / cm ³ or more. If the bulk density is less than 2.3 g / cm ³ , the fluidity, orientation performance, and magnetic properties of the composition may be deteriorated.

  The rare earth magnetic powder and the ferrite magnetic powder can be surface treated with a surface treating agent (D). Since the surface of the magnetic powder is coated by this surface treatment, a decrease in coercive force of the ferrite magnetic powder due to shear during kneading or injection molding is suppressed, and as a result, the squareness of the rare earth hybrid magnet is improved. In addition, the environmental resistance of the rare earth magnetic powder is also improved.

As the surface treatment agent (D), at least one selected from the group consisting of a phosphoric acid compound, a silane coupling agent, an aluminum coupling agent, and a titanate coupling agent is used.
Examples of the silane coupling agent include vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, β- (3,4 epoxy cyclohexylethyltrimethoxysilane), γ-glycidoxypropyltrimethoxysilane, γ- Glycidoxymethyldiethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl- γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, phenyltriethoxysila , Diphenyldiethoxysilane, isobutyltrimethoxysilane, decyltrimethoxysilane and the like.

Examples of titanium coupling agents include isopropyl triisostearoyl titanate, isopropyl tri (N-aminoethyl-aminoethyl) titanate, isopropyl tris (dioctyl pyrophosphate) titanate, tetraisopropyl bis (dioctyl phosphite) titanate, tetra Isopropyl titanate, tetrabutyl titanate, tetraoctyl bis (ditridecyl phosphite) titanate, isopropyl trioctanoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl tri (dioctyl phosphate) titanate, bis (dioctyl pyrophosphate) ethylene titanate, isopropyl di Methacrylisostearoyl titanate, tetra (2,2-diallyl Kishimechiru-1-butyl) bis (ditridecylphosphite) titanate, isopropyl tricumylphenyl titanate, bis (dioctyl pyrophosphate) oxy acetate titanate, isopropyl isostearoyl diacryl titanate.
Among these, the suitable thing according to the kind of resin binder can be selected, and those 1 type, or 2 or more types can be used.

3. Resin binder (C)
As the resin binder (C), various thermoplastic resins or thermosetting resins can be used, and their physical properties and properties are not particularly limited as long as desired properties are obtained.

  For example, in the case of thermoplastic resin, polyamide resin such as 6 nylon, 66 nylon, 11 nylon, 12 nylon, 6/12 nylon, aromatic nylon, modified nylon obtained by partially modifying these molecules, linear polyphenylene Sulfide resin, crosslinked polyphenylene sulfide resin, semi-crosslinked polyphenylene sulfide resin, low density polyethylene, linear low density polyethylene resin, high density polyethylene resin, ultrahigh molecular weight polyethylene resin, polypropylene resin, ethylene-vinyl acetate copolymer resin, ethylene -Ethyl acrylate copolymer resin, ionomer resin, polymethylpentene resin, polystyrene resin, acrylonitrile-butadiene-styrene copolymer resin, acrylonitrile-styrene copolymer resin, polyvinyl chloride resin, polyvinyl chloride Redene resin, polyvinyl acetate resin, polyvinyl alcohol resin, polyvinyl butyral resin, polyvinyl formal resin, methacrylic resin, polyvinylidene fluoride resin, polytrifluoroethylene chloride resin, tetrafluoroethylene-hexafluoropropylene copolymer resin, ethylene -Tetrafluoroethylene copolymer resin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin, polytetrafluoroethylene resin, polycarbonate resin, polyacetal resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyphenylene oxide resin, polyallyl ether Allyl sulfone resin, polyether sulfone resin, polyether ether ketone resin, polyarylate resin, aromatic polyester resin, cellulose acetate resin, various Elastomer and rubbers, and the like.

  In addition, random copolymers, block copolymers, graft copolymers, terminal group-modified products with other substances, and the like can be used. Further, a system in which two or more of these thermoplastic resins are blended is naturally included.

  Among these, polyamide resins such as 6 nylon, 66 nylon, 11 nylon, 12 nylon, 6/12 nylon, aromatic nylon, and modified nylon obtained by partially modifying these molecules, particularly the amount of residual soluble chlorine is 100 ppm or less. A polyamide resin is preferred. On the other hand, chlorine-containing resins such as polyvinyl chloride resin and polyvinylidene chloride resin are not preferable.

  The melt viscosity and molecular weight of these thermoplastic resins are preferably low as long as the desired mechanical strength can be obtained, and the shape is not particularly limited, such as powder, beads, pellets, etc., but considering the homogeneous mixing with magnetic powder Powder is desirable.

  On the other hand, in the case of thermosetting resin, epoxy resin, vinyl ester epoxy resin, unsaturated polyester resin, phenol resin, melamine resin, urea resin, benzoguanamine resin, bismaleimide / triazine resin, diallyl phthalate resin, furan resin, heat A curable polybutadiene resin, a polyimide resin, a polyurethane resin, a silicone resin, a xylene resin, and the like can be given. Of course, these basic compositions, other types of monomers, and systems obtained by blending two or more of these resins are also included.

  The viscosity, molecular weight, properties and the like of these thermosetting resins are not particularly limited as long as desired mechanical strength and moldability are obtained. The shape of the resin binder is preferably powder or liquid in view of uniform mixing with the magnetic powder and moldability.

  In addition, when producing the rare earth hybrid bonded magnet composition of the present invention, if a coupling agent, lubricant, stabilizer, etc. are used as additives, the heat fluidity of the composition is further improved, and the moldability and magnetic properties are improved. To do.

  Examples of the lubricant include waxes such as paraffin wax, liquid paraffin, polyethylene wax, polypropylene wax, ester wax, carnauba, and microwax, stearic acid, 1,2-oxystearic acid, lauric acid, palmitic acid, oleic acid, and the like. Fatty acid salts such as calcium stearate, barium stearate, magnesium stearate, lithium stearate, zinc stearate, aluminum stearate, calcium laurate, zinc linoleate, calcium ricinoleate, zinc 2-ethylhexoate (metal soap) ) Stearic acid amide, oleic acid amide, erucic acid amide, behenic acid amide, palmitic acid amide, lauric acid amide, hydroxystearic acid amide, methylene bis-stear Fatty acid amides such as acid amide, ethylenebisstearic acid amide, ethylene bislauric acid amide, distearyl adipic acid amide, ethylene bisoleic acid amide, dioleyl adipic acid amide, N-stearyl stearic acid amide, butyl stearate, etc. Fatty acid esters, alcohols such as ethylene glycol and stearyl alcohol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polyethers composed of these modified products, polysiloxanes such as dimethylpolysiloxane and silicone grease, fluorine-based oils, Fluorine compounds such as fluorine-based grease and fluorine-containing resin powder, inorganic compound powders such as silicon nitride, silicon carbide, magnesium oxide, alumina, silicon dioxide, molybdenum disulfide, and silica gel Etc. and the like, can be used alone or in combination.

  As stabilizers, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [2 -{3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy} ethyl] -4- {3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy} -2,2,6,6-tetramethylpiperidine, 8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,2,3-triazaspiro [4,5] undecane-2,4- Dione, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate Poly [[6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl] [(2,2,6,6-tetramethyl-4-piperidyl ) Imino] hexamethylene [(2,2,6,6-tetramethyl-4-piperidyl) imino], 2- (3,5-di-tert-butyl-4-hydroxybenzyl) -2-n-butylmalon In addition to hindered amine stabilizers such as bis (1,2,2,6,6-pentamethyl-4-piperidyl) acid, antioxidants such as phenols, phosphites, and thioethers can be used.

4). Composition for rare earth hybrid bonded magnet and preparation thereof The composition for rare earth hybrid bonded magnet of the present invention comprises (1) coating a rare earth magnetic powder with a surface treatment agent if necessary, and mixing ferrite magnetic powder thereto (2 ) It is prepared by blending the obtained mixed powder with a resin binder and, if necessary, other additives.

  In the present invention, the mixing ratio of the rare earth magnetic powder, the ferrite magnetic powder, and the resin binder is not particularly limited, and the mixing ratio of the rare earth magnetic powder and the ferrite magnetic powder and the resin binder of the target magnetic properties are not limited. It can be manufactured by appropriately setting the content rate.

  The ratio of the ferrite magnetic powder is not particularly limited, but is preferably 20 to 70% by weight, particularly 30 to 60% by weight based on the entire composition for the rare earth hybrid bonded magnet. If it is less than 20% by weight, a rare earth hybrid bonded magnet that is less expensive than the magnetic properties cannot be obtained, and if it exceeds 70% by weight, the magnetic properties may be deteriorated.

  If the mixing ratio, that is, (rare earth magnetic powder weight) / (ferrite magnetic powder weight) is set large with respect to the desired magnetic properties, the resin binder content can be increased, and as a result, the flow of the composition Improves. On the other hand, if the resin binder content is set to a small value, (rare earth magnetic powder weight) / (ferrite magnetic powder weight) can be reduced, which increases the content of ferrite magnetic powder. Cost can be reduced.

  Rare earth magnetic powder, ferrite magnetic powder and resin binder include, for example, blenders such as ribbon blenders, tumblers, nauter mixers, Henschel mixers, super mixers, planetary mixers, and banbury mixers, kneaders, rolls, kneader ruders, uniaxial The rare earth hybrid bonded magnet composition of the present invention can be obtained by mixing and kneading using a kneader such as an extruder or a twin screw extruder.

  In order to exhibit good weather resistance even in a high humidity environment, the residual chlorine content of the rare earth hybrid bonded magnet composition must be 150 ppm or less. The amount of residual chlorine in the composition is the concentration of chlorine (compound) generated by decomposing and distilling a sample in a mixed acid of nitric acid and sulfuric acid, and is analyzed by an ion chromatograph.

If the amount of residual chlorine exceeds 150 ppm, the weather resistance of the rare earth hybrid bonded magnet composition or the magnet is lowered, and the permanent demagnetization rate of the bonded magnet is increased or rust is easily generated in a humidity environment.
From the viewpoint of weather resistance, it is preferable to reduce the amount of residual chlorine in the composition as much as possible, but in order to make it less than 20 ppm, a step of reducing the amount of residual chlorine in the raw material to the limit is required, and ferrite magnetic powder and In some cases, the cost of the resin binder is increased, or a resin binder having sufficient magnetic properties cannot be obtained due to the influence of an additional process.

5). Rare earth hybrid bonded magnet The rare earth hybrid magnet of the present invention can be obtained by molding the composition for rare earth hybrid bonded magnet. The molding method is not particularly limited, and may be any one of injection molding, compression molding, extrusion molding, and rolling molding. In particular, injection molding or compression molding is preferable.

  When a composition using anisotropic rare earth magnetic powder is molded in a magnetic field, an anisotropic rare earth hybrid bonded magnet having a high magnetic flux density with uniform magnetization directions of the rare earth magnetic powder can be produced. That is, when using the R-Fe-N magnetic powder disclosed in JP-A-2-57663, etc., each powder is an anisotropic magnetic powder that is substantially a single crystal. By molding the composition in a magnetic field, an anisotropic rare earth hybrid magnet having a high magnetic flux density with uniform magnetization directions of the R—Fe—N magnetic powder can be produced.

  Similarly, an anisotropic rare earth hybrid bonded magnet having a high magnetic flux density can be produced by selecting an anisotropic magnetic powder and molding the ferrite magnetic powder in a magnetic field to align the easy magnetization direction of the ferrite magnetic powder. Therefore, if a composition using a combination of anisotropic rare earth magnetic powder and anisotropic ferrite magnetic powder is molded in a magnetic field, an anisotropic rare earth hybrid bonded magnet having a higher magnetic flux density can be obtained. .

  On the other hand, a hybrid magnet composed of a ferrite magnetic powder and an Nd—Fe—B rare earth magnetic powder disclosed in the above-mentioned Patent Document 4 (Japanese Patent Laid-Open No. 61-284906) or the like is an Nd—Fe—B based magnetism. Since the powder is isotropic, when obtaining the same magnetic flux density, the mixing ratio of the expensive rare earth magnetic powder must be set high, and the cost merit of the present invention cannot be obtained.

  When the rare earth hybrid bonded magnet of the present invention is formed into a molded body having a diameter of 10 mm and a height of 7 mm, the permanent demagnetization factor is less than −5% when left in a high temperature and high humidity environment of 95 ° C. and 95% RH for 300 hours. , Preferably less than −3%. If the permanent demagnetization factor exceeds -5%, it is not preferable because it causes a problem in terms of moisture resistance.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

The specific surface area A (m ² / g) and the average particle size B (m) of the ferrite magnetic powder were evaluated by an air permeation method using SS-100 manufactured by Shimadzu Corporation.
The residual soluble chlorine content of the ferrite magnetic powder was evaluated by ion chromatographic analysis of a solution obtained by extracting the powder with hot water with pure water. The amount of residual chlorine in the composition was evaluated by subjecting the sample to decomposition distillation under a mixed acid of nitric acid and sulfuric acid and performing ion chromatography analysis.
The weather resistance of the rare earth hybrid bonded magnet is determined by leaving the obtained magnet in a high temperature and high humidity environment of 95 ° C. and 95% RH for 300 hours (or 100 hours in a high temperature and high humidity environment of 60 ° C. and 70% RH). It was evaluated by confirming the permanent demagnetization rate and visual rust. Permanent demagnetization after flux phi ₀ and the high-temperature and high-humidity environmental test standing before wearing magnetizing was calculated by the following equation from the magnetic flux of the samples re-magnetized phi '. Here, the magnetizing condition of the magnet is a pulse magnetic field of 3350 kA / m.
Permanent demagnetization factor = {(φ′−φ ₀ ) / φ ₀ } × 100%
Visually, if the rare earth hybrid bonded magnet was not rusted, it was rated as ◯, and if rust was generated, it was marked as x.

(Examples 1-7)
Electrolytic Fe powder with a purity of 99.9 wt% and a particle size sieve opening of 0.104 mm (150 mesh, Tyler standard, the same shall apply hereinafter) and an oxide Sm with a purity of 99 wt% and an average particle size sieve opening of 0.043 mm (325 mesh) and less The powder and granular metal Ca having a purity of 99 wt% were mixed using a V blender. The mixture obtained here was put in a stainless steel container and heated at 1150 ° C. for 8 hours under an argon atmosphere to cause a reduction diffusion reaction. Next, the reaction product was cooled and then poured into water to be destroyed. The obtained slurry was washed with water and further acid washed with acetic acid to remove unreacted Ca and by-produced CaO. The obtained slurry was filtered and replaced with ethanol, and then vacuum-dried to obtain an Sm—Fe alloy powder of 150 μm or less.
Next, this powder was loaded into a tube furnace, heated in an ammonia-hydrogen mixed gas atmosphere with an ammonia partial pressure of 0.35 at 465 ° C. for 6 hours (nitriding treatment), and then heated in argon gas at 465 ° C. for 2 hours. (Annealing treatment) and 24.3 wt% Sm-3.6 wt% N-bal. An R—Fe—N alloy powder of Fe was obtained (bal. Represents the remainder).
X-ray analysis of this alloy powder showed a diffraction line (Sm ₂ Fe ₁₇ N ₃ intermetallic compound) having a rhombohedral Th ₂ Zn ₁₇ type crystal structure. This powder was finely pulverized to a Fischer average particle size of 1.6 μm using an impact plate jet mill to obtain anisotropic R—Fe—N magnetic powder.
Next, an R—Fe—N magnetic powder, an anisotropic Sr ferrite magnetic powder, and a 6/12 copolymer polyamide resin (the amount of soluble residual chlorine is less than 10 ppm) are mixed as a resin binder and kneaded in a lab plast mill. Thus, a composition for a rare earth hybrid bonded magnet was obtained. The respective contents are 49 wt% for the R—Fe—N magnetic powder, 40 wt% for the ferrite magnetic powder, and 11 wt% for the 6/12 copolymer polyamide resin. As the anisotropic Sr ferrite magnetic powder, a powder having a small amount of residual soluble chlorine and having an average particle size of less than 1 μm or small irregularities even if the average particle size is 1 to 10 μm was adopted. The kneading temperature was 200 to 220 ° C., and the composition taken out after kneading was air-cooled. Ρ of the Sr ferrite magnetic powder was set to 5.11 Mg / m ³ .
The obtained composition was pulverized with a plastic pulverizer to form pellets for molding. A cylindrical rare earth hybrid bond magnet of φ10 × 7 mm was produced from this pellet by injection molding while applying an orientation magnetic field of 560 kA / m in the 7 mm direction (column height direction). The cylinder temperature was 200 to 220 ° C, and the mold temperature was 60 ° C.
The results are shown in Table 1. In the table, the surface state is a value of A / (6 / (ρ × B)).

(Comparative Examples 1-4)
Cylindrical rare earth hybrid bonded magnets were produced in the same manner as described above except that the type of ferrite magnetic powder was changed and the amount of residual soluble chlorine was larger than that of the example and the amount of residual chlorine in the composition was larger. (Comparative Examples 1-3). Moreover, it experimented like Example 1 except having used the thing whose residual soluble chlorine amount is 110 ppm as a resin binder (comparative example 4). In this case, the amount of residual soluble chlorine in the composition was 161 ppm. The results are shown in Table 1.

(Reference Example 1)
Cylindrical rare earth hybrid bonded magnets were produced in the same manner as described above, except that the type of ferrite magnetic powder was changed and the residual soluble chlorine content was small but the surface was rough. The results are shown in Table 1.

"Evaluation"
A ferrite magnetic powder having a residual chlorine content of 30 to 300 ppm, a BET specific surface area of A (m ² / g), and an average particle diameter of B (m) is 1 × 10 ⁻⁶ or less. It can be seen that the R—Fe—N rare earth hybrid bonded magnet used has a permanent demagnetization rate of less than −5% and does not generate rust.
Further, when B is 3 × 10 ⁻⁶ or less and is larger than 1 × 10 ⁻⁶ , A / (6 / (ρ × B)) <2 (where ρ is 5.11 Mg / m ^3. However, it can be seen that the permanent demagnetization factor is less than -5% and rust does not occur. However, in other cases, it can be seen that the permanent demagnetization is greater than in the embodiment.

Here, it can be seen that the residual chlorine content of the composition is 150 ppm or less for those for which good results were obtained. The ferrite magnetic powders of Comparative Examples 1 and 2 had an angular shape when the surface was observed with a scanning electron microscope as compared with those of Examples 1-7.
The ferrite magnetic powder of Comparative Example 3 was round as in the examples, but the amount of residual soluble chlorine in the ferrite magnetic powder and the amount of residual chlorine in the composition exceeded 300 ppm and 150 ppm, respectively. It is thought that demagnetization has increased.
In Reference Example 1, the amount of residual soluble chlorine in the ferrite magnetic powder and the amount of residual chlorine in the composition are 300 ppm and 150 ppm or less, respectively, but the angular ferrite magnetic powder damages the surface of the R—Fe—N magnetic powder. It is considered that the permanent demagnetization is increased because of the above.

(Examples 8 to 14)
Rare earth hybrid bonded magnets were produced in the same manner as in Examples 1 to 7, except that isotropic Nd-Fe-B magnet powder (MQP-13-9) manufactured by Magnequench International was used as the rare earth magnetic powder. .
The content of the rare earth magnetic powder was 62 wt%, the ferrite magnetic powder was 29 wt%, and the resin binder (12 polyamide) was 9 wt%. Ρ of the Sr ferrite magnetic powder was set to 5.11 Mg / m ³ .
Moreover, the weather resistance of the rare earth hybrid bonded magnet was evaluated in the same manner as in Examples 1 to 7 except that it was evaluated in a high temperature and high humidity environment of 60 ° C. and 70% RH for 100 hours. The results are shown in Table 2. In the table, the surface state is a value of A / (6 / (ρ × B)).
In the rare earth hybrid bonded magnets of the examples, the permanent demagnetization rates were all less than −5% when left in a high temperature and high humidity environment of 95 ° C. and 95% RH for 300 hours.

(Comparative Examples 5 to 8)
Cylindrical rare earth hybrid bonded magnets were produced in the same manner as described above except that the type of ferrite magnetic powder was changed and the amount of residual soluble chlorine was larger than that of the example and the amount of residual chlorine in the composition was larger. (Comparative Examples 5 to 7). Moreover, it experimented like Example 8-14 except having used the thing whose residual soluble chlorine amount is 110 ppm as a resin binder (comparative example 8). In this case, the amount of residual soluble chlorine in the composition was 168 ppm. The results are shown in Table 2.

(Reference Example 2)
Cylindrical rare earth hybrid bonded magnets were produced in the same manner as described above, except that the type of ferrite magnetic powder was changed and the residual soluble chlorine content was small but the surface was rough. The results are shown in Table 2.

"Evaluation"
R using a ferrite magnetic powder having a residual chlorine amount of 30 to 300 ppm and B ≦ 1 × 10 ⁻⁶ when the BET specific surface area A (m ² / g) and the average particle diameter B (m) are used. In the —Fe—B rare earth hybrid bond magnet, the permanent demagnetization rate is less than −2%, and no rust is observed. Further, when B> 1 × 10 ⁻⁶ , A / (6 / (ρ × B)) <2 (where ρ is 5.11 Mg / m ³ ), but the permanent demagnetization factor is less than −2% and rust The occurrence of is also not seen. However, in other cases, rust is generated and it can be seen that permanent demagnetization is greater than in the examples.

Here, it can be seen that the residual chlorine content of the composition is 150 ppm or less for those for which good results were obtained.
The ferrite magnetic powder of Comparative Example 7 was round as in the examples, but the amount of residual soluble chlorine in the ferrite magnetic powder and the amount of residual chlorine in the composition exceeded 300 ppm and 150 ppm, respectively. It is thought that demagnetization was large and rust was also generated.
In Reference Example 2, the amount of residual soluble chlorine in the ferrite magnetic powder and the amount of residual chlorine in the composition were 300 ppm and 150 ppm or less, respectively, but the angular ferrite magnetic powder damaged the surface of the R-Fe-B magnetic powder. Therefore, it is considered that permanent demagnetization is large and rust is also generated.

Claims (6)

In the rare earth hybrid powder composition comprising, as a main component, a rare earth magnetic powder (A) , a ferrite magnetic powder (B) selected from Sr ferrite or Ba ferrite , and a resin binder (C).
The amount of residual soluble chlorine in the ferrite magnetic powder (B) is 30 to 300 ppm, the amount of residual chlorine in the entire composition is 150 ppm or less, and the average particle size of the ferrite magnetic powder (B) is 3 μm or less. And when it exceeds 1 micrometer, the relational expression represented by following Formula is satisfied , The composition for rare earth hybrid bond magnets characterized by the above-mentioned.
A / (6 / (ρ × B)) <2
[In the formula, A represents the BET specific surface area (m ² / g) of the ferrite magnetic powder, ρ represents the true density (Mg / m ³ ) of the ferrite magnetic powder, and B represents the average particle diameter (m) of the ferrite magnetic powder]   2. The rare earth hybrid bonded magnet according to claim 1, wherein the rare earth based magnetic powder (A) is a rare earth based magnetic powder mainly composed of a rare earth element, iron or iron and cobalt, and nitrogen or boron. Composition.   The composition for a rare earth hybrid bonded magnet according to claim 1, wherein the ratio of the ferrite magnetic powder (B) is 20 to 70% by weight based on the whole composition.   The composition for rare earth hybrid bonded magnet according to claim 1, wherein the resin binder (C) is a polyamide resin, and the amount of residual soluble chlorine is 100 ppm or less. The rare earth hybrid bonded magnet composition according to any one of claims 1 to 4 is molded by at least one molding method selected from an injection molding method, a compression molding method, an extrusion molding method, or a rolling molding method. Rare earth hybrid bonded magnet. 6. The rare earth hybrid bond magnet according to claim 5 , wherein the permanent demagnetization factor when left in a high temperature and high humidity environment of 95 [deg.] C. and 95% RH for 300 hours is less than -5%.