JP2018081970A - Iron-based magnet alloy powder including rare earth element, method for manufacturing the same, rare earth composition for bond magnet, and rare earth magnet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: iron-based magnet alloy powder including a rare earth element and having excellent salt water resistance; a rare earth composition for a bond magnet, which has excellent fluidity and moldability; and a rare earth magnet having an excellent magnetic property and high salt water resistance.SOLUTION: Iron based magnet alloy powder including a rare earth element comprises: a first composite metal phosphate coating formed on the surface of magnet alloy powder; and a second composite metal phosphate coating formed on the surface of the first composite metal phosphate coating, including an allyl compound having a benzene ring or isocyanurate ring. In the iron-based magnet alloy powder, an addition amount of the allyl compound added to the second composite metal phosphate coating is 0.1-5 mass% to a total mass of the magnet alloy powder. The iron-based magnet alloy powder including a rare earth element is used to manufacture a rare earth composition for a bond magnet, and a rare earth bond magnet or rare earth compacted magnet.SELECTED DRAWING: None

Description

  The present invention relates to an iron-based magnet alloy powder containing a rare earth element and a method for producing the same, a composition for a rare earth bonded magnet comprising a magnet alloy powder and a resin binder, a rare earth bonded magnet that is a resin-bonded magnet, and a magnet alloy powder The present invention relates to a rare earth compacted magnet.

  Ferrite magnets, alnico magnets, and rare earth magnets are widely used as motors and sensors in various products including general home appliances, communication equipment, acoustic equipment, medical equipment, and general industrial equipment. These magnets are mainly manufactured by a powder sintering method, but these magnets obtained by the powder sintering method are brittle and difficult to thin, and thus are difficult to form into complex shapes. Magnets obtained by the powder sintering method due to demerits such that the dimensional accuracy cannot be increased and post-processing such as polishing is necessary because it shrinks by 15% to 20% during sintering. Are severely restricted in their application.

  In contrast, bonded magnets (also called resin-bonded magnets) are made of thermoplastic resin such as polyamide resin and polyphenylene sulfide resin, or heat such as epoxy resin, bis-maleimide triazine resin, unsaturated polyester resin, and vinyl ester resin. A resin binder obtained by adding a curing agent to a plastic resin, mixing and kneading the resin binder and magnet alloy powder to obtain a bonded magnet composition, and further molding the bonded magnet composition Is obtained. Bonded magnets have the advantage that they are easy to process and can be formed into complex shapes, so they can be widely applied to applications such as small motors and small sensors, and are actively developing new applications. Has been done.

  Among bond magnets, rare earth bond magnets using rare earth elements containing rare earth elements such as neodymium magnets and samarium iron nitrogen (Sm-Fe-N) magnets are mixed and kneaded with the magnet alloy powder and resin binder. The rare earth bonded magnet composition is produced by molding, but in order to obtain the rare earth bonded magnet composition, it is necessary to pulverize the magnet alloy powder to about several μm. The pulverization is carried out in an inert gas or an organic solvent. However, the activity of the powder surface after pulverization is extremely high, and the magnetic alloy powder rapidly oxidizes when exposed to the air, thereby deteriorating its magnetic properties. In order to suppress rapid oxidation when taken out into the air after pulverization, a slight amount of oxygen is introduced into an inert atmosphere after pulverization to gradually oxidize the surface of the fine powder.

  Moreover, the bond magnet using the obtained iron-based magnet alloy powder containing rare earth elements has a demerit that rust is easily generated in salt water. On the other hand, for example, as described in JP-A No. 2000-208321, a coating film such as a thermosetting resin is formed on the surface of the molded rare earth bonded magnet, or a phosphate. It has been proposed to suppress the rusting by applying a coating treatment with the contained paint. However, even a rare-earth bonded magnet that has been subjected to such a coating treatment has not been sufficiently effective in suppressing rusting in a corrosive environment such as salt water.

  On the other hand, as described in JP-A-1-14902, JP-A-64-15301, JP-A-4-257202, JP-A-7-142246, etc. Applying chemical conversion treatment such as phosphate treatment and chromate treatment to the surface of iron-based magnet alloy powder containing rare earth elements, which is a raw material for the above, vapor deposition of zinc and aluminum, and forming a polymer coating It has been proposed to coat the surface of the magnet alloy powder itself by, for example, metal plating to prevent oxidative deterioration of the magnet alloy powder in the manufacturing process and oxidative deterioration of the rare earth bonded magnet after molding. .

  When these means are applied to a magnet alloy powder for a samarium iron nitrogen magnet, an increase in kneading torque can be suppressed to some extent when kneading a mixture of the magnet alloy powder and a binder resin. It is considered that the acid-base interaction between the magnet alloy powder and the resin binder and the influence of metal ions derived from the magnet alloy powder can be suppressed to some extent. However, these means have a problem that the surface properties of the magnet alloy powder are roughened and the magnetic properties of the obtained magnet are deteriorated. In addition, in order to impart sufficient salt water resistance and oxidation resistance to the coating, the thickness of the coating needs to be about several tens of μm. For this reason, there is a problem in that the volume fraction of the magnetic alloy powder that exhibits magnetic characteristics is lowered, and the magnetic characteristics are similarly lowered. Furthermore, in these means, when the coating is formed, the fine powders constituting the magnetic alloy powder also aggregate, so that the movement of the individual fine powders is restricted when a magnetic field is applied, and the anisotropic magnet In this case, it is difficult to align the direction of easy magnetization of the magnet alloy powder, and it is inevitable that the magnetic properties of the magnet after molding will deteriorate.

In addition, when the magnetic alloy powder is coated with a phosphoric acid compound, hydrogen ions are ionized when the phosphoric acid compound is dissolved in water, and the treatment liquid shows acidity. When this acidic solution and the magnetic alloy powder are mixed, On the surface of the magnet alloy powder, hydrogen ions receive electrons from the magnet alloy powder and are reduced to hydrogen molecules (H ₂ ). By this reduction reaction, the magnet alloy powder loses electrons and becomes positively charged, and a phosphoric acid compound having a negative charge is deposited on the surface of the magnet alloy powder. As this reduction reaction proceeds, the hydrogen ion concentration of the treatment liquid decreases and the pH increases. When the speed of this reduction reaction is high, the above-described reaction occurs in a short time, and the rate of change in pH increase is also increased. As the value of the rate of change in pH increase increases, the rate of precipitation of the phosphate compound increases, so that the precipitated phosphate compound tends to aggregate.

  On the other hand, for example, JP 2002-8911 A employs a phosphoric acid compound having a low rate of change in pH, suppresses the precipitation rate of the phosphoric acid compound, and aggregates the precipitated phosphoric acid compound particles. A method for preventing the formation of the coating densely without reducing the adhesion between the magnetic powder and the phosphate is disclosed. However, in the magnetic alloy powder produced by this method, although the influence of the acid-base interaction between the magnetic alloy powder and the resin binder and the influence of metal ions derived from the magnetic alloy powder can be suppressed to some extent, X-ray photoelectron spectroscopy ( The XPS analysis confirms that Fe metal is present in the coating, and it cannot be said that a sufficiently dense coating is formed. Therefore, when a bonded magnet produced using the above magnet alloy powder is immersed in salt water for 24 hours, the generation of rust can be reduced to some extent, but the generation cannot be completely suppressed.

  Also, for example, in JP-A-2006-169618, in order to improve the mechanical strength of a bonded magnet and to suppress the occurrence of rust in salt water, an iron-based magnet alloy roughening containing a rare earth element is disclosed. When the powder is pulverized in an organic solvent, or after the pulverization, phosphoric acid is added and stirred, and a composite metal phosphate coating containing iron phosphate and rare earth metal phosphate on the surface of the magnet alloy powder And then separating and removing the solution from the magnetic alloy powder slurry, mixing and stirring the alkoxysilicate, hydrolyzing the alkoxysilicate, and forming a silicate coating on the surface of the composite metal phosphate coating. A method for producing a magnet alloy powder having a forming step is disclosed. Although this method can improve the mechanical strength of the bonded magnet and has some effect of suppressing the occurrence of rust in salt water, it is confirmed by XPS analysis that Fe metal is also present in the coating. Therefore, there is room for improvement in terms of improving the fluidity Q value that is an index of injection moldability.

  In recent years, in the fields of motors for home appliances, motors for automobiles, and sensors for automobiles, since the products are assembled overseas, the parts are required to be transported by ship etc. Further, it is becoming stricter, and downsizing of parts of these products is strongly demanded. Therefore, the rare earth bonded magnet and the magnet alloy powder used therefor are required to have both excellent magnetic properties and high salt water resistance.

  In addition to rare earth bonded magnets, rare earth compacted magnets in which an iron-based magnet alloy powder containing rare earth elements is consolidated to have an apparent density of 85% or more of the true density are the same as rare earth bonded magnets. There is a problem of corrosion resistance and salt water resistance in the magnet itself and its raw material powder. Therefore, both the rare earth compacted magnet and the magnet alloy powder used therefor are required to have both excellent magnetic properties and high salt water resistance.

JP 2000-208321 A Japanese Patent Laid-Open No. 1-14902 JP-A-64-15301 JP-A-4-257202 Japanese Patent Laid-Open No. 7-142246 JP 2002-8911 A JP 2006-169618 A

  The object of the present invention is to oxidize the magnet alloy powder in the magnet manufacturing process without damaging the surface properties of the magnet alloy powder containing rare earth elements and without forming a thick film in view of the above-mentioned problems of the prior art. The present invention provides a film forming means capable of preventing deterioration and suppressing the occurrence of aggregation of fine powders constituting a magnetic alloy powder, and thus has a composition for a rare earth bonded magnet having excellent fluidity and formability, and Another object of the present invention is to provide a rare earth bonded magnet and a rare earth compacted magnet having excellent magnetic properties and high salt water resistance.

  As a result of intensive studies to solve the above problems, the present inventors have found that the first composite metal phosphorus containing iron phosphate and rare earth metal phosphate is formed on the surface of the iron-based magnet alloy powder containing rare earth elements. A second composite metal comprising an acid salt film, and further comprising an allyl compound having a benzene ring or an isocyanurate ring on the surface of the first composite metal phosphate film, iron phosphate and a rare earth metal phosphate By forming a phosphate coating, that is, by forming a multilayer composite metal phosphate coating containing an allyl compound having a benzene ring or an isocyanurate ring, a magnet alloy powder stable in the atmosphere can be obtained, Composition for rare earth bonded magnet having excellent fluidity and formability by using magnet alloy powder, and rare earth bonded magnet having excellent magnetic properties and high salt water resistance And rare earth consolidation magnet to obtain a knowledge of to be obtained. Based on this finding, the present inventors have completed the present invention.

  That is, in one aspect, the present invention provides an iron-based magnet alloy powder containing a rare earth element, the first composite containing iron phosphate and a rare earth metal phosphate formed on the surface of the magnet alloy powder. A metal phosphate coating; a second compound comprising an allyl compound having a benzene ring or an isocyanurate ring formed on the surface of the first composite metal phosphate coating; and an iron phosphate and a rare earth metal phosphate. And an addition amount of the allyl compound added to the second composite metal phosphate coating is 0.1% by mass to the total mass of the magnet alloy powder. Provided is an iron-based magnet alloy powder containing a rare earth element at 5% by mass.

  In one embodiment, the average thickness of the entire first and second composite metal phosphate coating is 28 nm or more.

  In one embodiment, the magnet alloy powder has an average particle size of 8 μm or less.

  In one embodiment, the first composite metal phosphate coating further contains one or more selected from Al, Zn, Mn, Cu, and Ca as a metal component.

In one aspect, the present invention provides:
An iron-based magnet alloy coarse powder containing a rare earth element is put into an organic solvent to which phosphoric acid is added, and the magnet alloy coarse powder is pulverized to form phosphoric acid on the surface of the iron-based magnet alloy powder containing the rare earth element. Forming a first composite metal phosphate coating comprising iron and a rare earth metal phosphate;
Separating and recovering the magnet alloy powder from the slurry containing the magnet alloy powder, and subjecting the magnet alloy powder to a heat treatment of 100 ° C. or higher under reduced pressure;
By introducing the magnet alloy powder after the heat treatment into an organic solvent to which an allyl compound having a benzene ring or an isocyanurate ring and phosphoric acid are added, and pulverizing the magnet alloy powder, Forming a second composite metal phosphate coating comprising the allyl compound, iron phosphate and rare earth metal phosphate on the surface of the first composite metal phosphate coating;
Separating and recovering the magnet alloy powder from the slurry containing the magnet alloy powder provided with the first and second composite metal phosphate coatings, and subjecting the magnet alloy powder to a heat treatment at 100 ° C. or higher under reduced pressure; ,
A method for producing an iron-based magnet alloy powder containing a rare earth element is provided.

  In one embodiment, the organic solvent used in the step of forming the first and second composite metal phosphate films is N, N-dimethylformamide, formamide, 2-methoxyethanol, ethanol, methanol, and One or more selected from isopropyl alcohol.

  In one embodiment, the phosphoric acid in the step of forming the first and second composite metal phosphate coatings is 0.1 mol / kg to 2 mol / kg per mass with respect to the magnet alloy powder. The addition amount is in the range of.

  In one embodiment, in the step of forming the first composite metal phosphate coating, a metal component containing at least one selected from Al, Zn, Mn, Cu, and Ca is added.

  In one aspect, the present invention provides a composition for a rare earth bonded magnet comprising an iron-based magnet alloy powder containing the rare earth element of the present invention and a resin binder made of a thermoplastic resin or a thermosetting resin.

  In one aspect, the present invention provides a rare earth bonded magnet obtained by molding the rare earth bonded magnet composition of the present invention. In other words, the present invention provides a rare earth bonded magnet obtained by bonding the iron-based magnet alloy powder containing the rare earth element of the present invention with a thermoplastic resin or a thermosetting resin.

  In another aspect, the present invention comprises an iron-based magnet alloy powder containing the rare earth element of the present invention, and is obtained by consolidating the magnet alloy powder so that the apparent density is 85% or more of the true density. A rare earth compacted magnet is provided.

  The iron-based magnet alloy powder containing the rare earth element of the present invention is formed on the surface of the first composite metal phosphate coating and the first composite metal phosphate coating formed on the surface of the magnet alloy powder. And a second composite metal phosphate coating containing an allyl compound having a benzene ring or an isocyanurate ring, so that only one composite metal phosphate coating is formed on the surface of the magnet alloy powder. Compared to existing magnet alloy powder, it is a stable magnet alloy powder in the atmosphere.

  Moreover, since the rare earth bond magnet composition containing the magnet alloy powder and the resin binder has high fluidity and formability, it is possible to form a rare earth bond magnet with high formability. Furthermore, the iron-based magnet alloy powder containing the rare earth element of the present invention is excellent in corrosion resistance, and has excellent magnetic properties of the rare earth magnet with respect to the rare earth bonded magnet and the rare earth compacted magnet obtained by using the magnet alloy powder. While maintaining, high salt water resistance can also be imparted. That is, since it becomes possible to apply a rare earth magnet having excellent magnetic properties to a motor for home appliances, a motor for automobiles and a sensor for automobiles with high salt water resistance and excellent shape accuracy, the industry of the present invention. Target value is extremely high.

  Hereinafter, the iron-based magnet alloy powder containing a rare earth element of the present invention, a method for producing the same, a composition for a rare earth bonded magnet, and a rare earth magnet will be described in detail.

1. Iron-based magnet alloy powder containing rare earth element The iron-based magnet alloy powder containing rare earth element of the present invention is a first composite metal containing iron phosphate and rare earth metal phosphate formed on the surface of the magnet alloy powder. A second composite comprising a phosphate coating, an allyl compound having a benzene ring or an isocyanurate ring, iron phosphate and a rare earth metal phosphate formed on the surface of the first composite metal phosphate coating And the addition amount of the allyl compound added to the second composite metal phosphate coating is 0.1% by mass to 5% with respect to the total mass of the magnet alloy powder. It is characterized by mass%.

(1) Iron-based magnet alloy powder containing rare earth elements The magnet alloy powder applied to the present invention is not particularly limited as long as it is an iron-based magnet alloy powder containing rare earth elements. For example, rare earth element-iron-boron magnets such as neodymium magnets (Nd ₂ Fe ₁₄ B), rare earth element-iron-nitrogen magnets such as samarium iron nitrogen (Sm—Fe—N) magnets, samarium cobalt magnets (SmCo _5). And the present invention can be applied to powders of iron-based magnet alloys containing various rare earth elements such as Sm ₂ Co ₁₇ ) and praseodymium magnets (PrCo ₅ ).

  The rare earth elements include Sc (scandium), Y (yttrium), and lanthanoids. In particular, the present invention provides a rare earth element-iron-boron magnet and a rare earth element-iron-nitrogen magnet alloy, particularly a rare earth element-iron-nitrogen magnet alloy, which have high magnetic properties and have the property of being easily rusted. It is suitably applied to the powder of As rare earth elements applied to rare earth element-iron-nitrogen based magnet alloy powders, Sm (samarium), Nd (neodymium), Pr (praseodymium), Y, La (lanthanum), Ce (cerium), Gd (gadolinium) These rare earth elements are used alone or in combination. Among these rare earth element-iron-nitrogen based magnet alloy powders, in particular, samarium iron nitrogen (Sm—Fe—N) magnet alloy powder containing 5 to 40 atomic% of Sm or Nd and 50 to 90 atomic% of Fe, Or this invention is applied suitably with respect to neodymium iron nitrogen (Nd-Fe-N) magnet alloy powder.

  In producing an iron-based magnet alloy powder containing a rare earth element, first, a rare earth element-iron-based master alloy coarse powder is prepared by a reduction diffusion method, a high-frequency melting method, an arc melting method, or a strip casting method.

  When the reduction diffusion method is used, a predetermined amount of rare earth oxide powder, iron powder, and other raw material powders are mixed, and a reducing agent sufficient to reduce the rare earth oxide powder is added and mixed. The mixture is charged into a reaction vessel, and in a non-oxidizing atmosphere (an atmosphere in which oxygen is not substantially present), a temperature at which the reducing agent melts is 800 ° C. or higher, and a temperature at which the rare earth element-iron master alloy does not melt The rare earth oxide is reduced to a rare earth element by performing a heat treatment for raising and maintaining the temperature until the rare earth element is diffused into the iron powder to synthesize a rare earth element-iron-based alloy.

  The rare earth oxide powder is not particularly limited, but in the case of the rare earth element-iron-nitrogen based magnet alloy powder, it contains at least one rare earth element selected from Sm, Gd, Tb (terbium), and Ce, Alternatively, these rare earth elements and at least one rare earth element selected from Pr, Nd, Dy (dysprosium), Ho (holmium), Er (erbium), Tm (thulium), and Yb (ytterbium) Rare earth oxide powders are preferred. In these, the rare earth oxide powder containing Sm is preferable. When Sm is included, in order to obtain a high coercive force, it is more preferable to use rare earth oxide powder having Sm of 60% by mass or more, more preferably 90% by mass or more of the entire rare earth element.

  In addition, the rare earth oxide powder has a predetermined amount of Mn (manganese), Ca (calcium), Cr (chromium), Nb (niobium), Mo in order to improve coercive force, improve productivity, and reduce costs. One selected from (molybdenum), Sb (antimony), Ge (germanium), Zr (zirconium), V (vanadium), Si (silicon), Al (aluminum), Ta (tantalum), and Cu (copper) The above may be added. The particle size of the rare earth oxide powder is not particularly limited, but the particle size is preferably 10 μm or less from the viewpoint of reactivity and workability.

  The iron powder is not particularly limited, and any of reduced iron powder, gas atomized powder, water atomized powder, carbonyl iron powder, electrolytic iron powder, and the like can be used. Moreover, the iron powder which substituted 20 mass% or less of iron with cobalt can also be used. Regarding the particle properties of the iron powder, the average particle size is in the range of 35 μm to 45 μm, and the powder in the range of the particle size is in the range of 5 μm to 60 μm occupies 80% by volume or more of the total iron powder. Is preferred. If the particle size of the iron powder is too large, it takes a very long time for the rare earth element to diffuse into Fe when the rare earth element-iron alloy is synthesized. On the other hand, since iron powder with a small particle size is expensive, a burden becomes large in terms of manufacturing cost.

  The reducing agent is not particularly limited, and alkali metals, alkaline earth metals, hydrides thereof, and the like can be used. In terms of handling safety and cost, granular metal calcium sieved and classified to 5 mesh (Tyler mesh) or less is preferably used.

  The above rare earth oxide powder, iron powder, and reducing agent are weighed in predetermined amounts, and then these powders are thoroughly mixed. For mixing, for example, a known mixing device such as a V-shaped blender or an S-shaped blender can be used.

  Next, the reaction product obtained by the reduction diffusion treatment is charged into a sealed container, and after evacuation, the reaction product is occluded with hydrogen by performing hydrogen treatment under a predetermined condition. As a result, the pulverization property of the reaction product and the disintegration property in water are improved, and the reaction product can be finely pulverized by subsequent water disintegration treatment and water washing treatment without crushing treatment. -The oxidation of the surface of the iron-based mother alloy coarse powder can be suppressed.

Moreover, since the hydrogen treatment has the effect of improving the disintegration property of the reduced product and dissociating the sintered particles, the excess rare earth element-rich phase can be easily removed by pickling. Here, the mechanism of the hydrogen treatment having such an effect will be specifically described below. For example, an Sm-Fe alloy synthesized by the reduction diffusion method has an Sm-rich phase (SmFe ₂ , SmFe ₃ ) around the main phase (Sm ₂ Fe ₁₇ ), and the Sm-Fe alloy is used as a reaction vessel. When left in hydrogen, the main phase and Sm rich phase change to Sm ₂ Fe ₁₇ H _x , SmFe ₂ H _x and SmFe ₃ H _x , respectively. At this time, the Sm-rich phase around the main phase has a larger lattice expansion coefficient than the main phase, so the Sm-rich phase breaks, and as a result, the reduced product collapses.

  Next, the reaction product containing the obtained rare earth element-iron alloy is cooled to room temperature by air cooling and furnace cooling, and then poured into pure water for disintegration treatment, and calcium oxide or metallic calcium. As such, the remaining reducing agent is dissolved and removed. As the water washing treatment, a slurry mainly composed of a rare earth element-iron-based alloy powder is obtained by performing stirring and decantation a predetermined number of times.

  Further, pickling treatment is performed on the obtained slurry. In the pickling treatment, the remaining calcium hydroxide and the like are removed, and the rare earth element rich phase generated by the rare earth element added excessively to keep the surface state of the powder active is removed. At this time, acetic acid, hydrochloric acid, nitric acid, sulfuric acid and the like are used as the acid used for the pickling treatment.

  By subjecting the obtained powder to a water washing treatment and a drying treatment for removing acid, a rare earth element-iron-based alloy coarse powder can be obtained.

  On the other hand, in a melting method such as a high frequency melting method or an arc melting method, a rare earth element-iron alloy is prepared by blending and melting a component metal or a master alloy in accordance with a target composition and pulverizing an ingot obtained by casting. A coarse powder is obtained. The melting method must use an expensive and active rare earth metal as a raw material, the primary crystal of Fe is segregated at the time of casting, so the uniformity of the alloy structure is inferior, and the ingot crushing step is necessary However, it is difficult to contain oxygen during casting, and the rare earth metal phase that is easily oxidized is greatly segregated, so that oxidation in the grinding process can be easily suppressed, and the alloy powder has a relatively low oxygen content. Can be obtained.

  In the strip casting method, an alloy having a composition of a rare earth element-iron-based master alloy is melted by high-frequency melting in an argon atmosphere to form a molten alloy, and the molten alloy is brought into contact with the surface of a cooling roll, By cooling, a ribbon of a quenched alloy is produced and pulverized to obtain a rare earth element-iron alloy coarse powder. Specifically, after the molten alloy is maintained at about 1350 ° C., it is rapidly cooled by a single roll method, for example, under rapid cooling conditions such as a roll peripheral speed of about 1 m / sec, a cooling rate of 500 ° C./sec, and a supercooling of 200 ° C. For example, a quenched alloy slab having a thickness of about 0.3 mm is obtained. Next, the quenched alloy slab is pulverized into flakes having a size in the range of 1 mm to 10 mm, and the flaky alloy slab is vacuum-evacuated and then supplied with hydrogen gas to form a hydrogen atmosphere. Inserted inside, hydrogen pulverization treatment (also called hydrogen embrittlement treatment) is performed at a hydrogen pressure of about 200 kPa to 400 kPa. Thereby, a mother alloy coarse powder having a particle size of about 0.1 mm to several mm and an average particle size of about 500 μm or less is obtained. Furthermore, the embrittled mother alloy coarse powder is heated under reduced pressure of about 3 Pa or less, dehydrogenated, and then cooled while supplying argon gas into the furnace using a cooling device such as a rotary cooler. The mother alloy coarse powder can be crushed more finely.

In the case of rare earth element-iron-nitrogen based magnet alloy powder, the rare earth element having a particle diameter in the range of several tens to several hundreds of μm obtained by the above reduction diffusion method, dissolution method, or strip casting method— The iron-based mother alloy coarse powder is subjected to a gas phase-solid phase reaction with nitrogen gas, a mixed gas of nitrogen and ammonia, or a mixed gas of nitrogen and hydrogen, so that nitrogen is interposed between the crystal lattices of the rare earth element-iron-based mother alloy. To obtain a rare earth element-iron-nitrogen based magnet alloy coarse powder having a crystal structure such as Sm ₂ Fe ₁₇ N _x .

  The obtained coarse powder is subjected to dry mechanical pulverization such as jet mill pulverization in a nitrogen atmosphere, and wet mechanical pulverization such as ball mill pulverization or medium agitation mill pulverization in an organic solvent such as alcohol, so that the average particle size is 8 μm. Hereinafter, an iron-based magnet alloy powder containing a rare earth element such as a rare earth element-iron-nitrogen-based magnet alloy powder, which is preferably a fine powder in the range of 5 μm or less, more preferably in the range of 1 μm to 3 μm, is obtained. This pulverization treatment is a treatment necessary for improving the magnetic performance (coercive force) of the rare earth magnet using the iron-based magnet alloy powder containing the rare earth element. That is, according to the single-domain fine particle theory, the magnetic performance (coercive force) of a magnet using the magnet powder can be basically improved as the particle diameter of the magnet powder is reduced.

The obtained iron-based magnet alloy powder containing rare earth elements can be mixed with various magnet alloy powders that are raw materials for rare earth bonded magnets and rare earth compacted magnets, such as ferrite magnet powders and alnico magnet powders. As these various magnet alloy powders, not only anisotropic magnet alloy powders, but also isotropic magnet alloy powders can be mixed with iron-based magnet alloy powders containing rare earth elements. It is preferable to use an anisotropic magnet alloy powder having H _A ) of 4.0 MA / m or more, and the present invention is also suitably applied.

  Further, in order to use the above various magnet alloy powders as raw materials for rare earth bonded magnets and rare earth compacted magnets, the average particle size is preferably 8 μm or less, particularly 5 μm or less, and more preferably in the range of 1 μm to 3 μm. If the average particle size exceeds 8 μm, the formability of the iron-based magnet alloy powder containing rare earth elements and the composition using this powder is not preferable.

(2) First composite metal phosphate coating In the present invention, the magnet alloy powder containing a rare earth element is a first composite metal phosphate containing iron phosphate and rare earth metal phosphate formed on the surface thereof. It is uniformly coated with a salt coating. The metal phosphate constituting the first composite metal phosphate coating is samarium phosphate, iron phosphate or the like, which is formed by reacting phosphoric acid with rare earth elements or iron constituting the magnet alloy powder. It is a thing.

  In addition, the metal phosphate constituting the first composite metal phosphate coating further contains at least one metal component of Al, Zn (zinc), Mn, Cu, and Ca to form a composite. Also included are metal phosphates. Specifically, in this composite metal phosphate, in addition to iron phosphate and rare earth metal phosphate, aluminum phosphate, zinc phosphate, manganese phosphate, copper phosphate, calcium phosphate, or two or more thereof The metal component phosphate is complexed. In addition to Al, Zn, Mn, Cu, and Ca, examples of the metal component include Cr, Ni (nickel), Mg (magnesium), and the like. It may be contained in the metal phosphate coating.

  Here, uniformly coated means that 80% or more, preferably 85% or more, more preferably 90% or more of the surface of the magnet alloy powder is covered with the first composite metal phosphate coating. Means.

  The metal phosphate constituting the first composite metal phosphate coating is a component that enhances the bonding strength between the magnet alloy powder and the resin binder and increases the corrosion resistance of the magnet alloy powder. Sufficient salt water resistance can be obtained with only metal phosphates including iron phosphate and rare earth metal phosphates, but further, metal components such as Al, Zn, Mn, Cu, and Ca are the first composite metal. It is preferable that 30 mass% or more, especially 50 mass% or more, more preferably 80 mass% or more is contained with respect to the total amount of metal components (iron, rare earth elements and additive metal components) in the phosphate coating.

  The average thickness of the first composite metal phosphate coating is in the range of 1 nm to 100 nm, and preferably in the range of 5 nm to 40 nm. When the average thickness of the first composite metal phosphate coating is less than 1 nm, the surface of the magnet alloy powder cannot be sufficiently covered, and sufficient salt water resistance and mechanical strength cannot be obtained. On the other hand, if the average thickness exceeds 100 nm, the density of the magnet alloy powder cannot be increased, and the magnetic properties of the obtained rare earth magnet will be reduced. Also, for rare earth bonded magnets using the magnet alloy powder. The kneadability at the time of producing the composition is lowered, or the moldability of the magnet alloy powder and the composition for rare earth bonded magnet is lowered. The average thickness of the first composite metal phosphate coating is a plurality of powders obtained from an electron micrograph of a cross section of an iron-based magnet alloy powder containing a rare earth element coated with the first composite metal phosphate coating It is the average value (5-point average value) of the numerical value which measured the film thickness of arbitrary 5 places.

(3) Second composite metal phosphate coating In the iron-based magnet alloy powder containing rare earth elements of the present invention, the first composite iron phosphate and rare earth metal phosphate formed on the surface of the magnet alloy powder. In addition to the composite metal phosphate coating, an allyl compound having a benzene ring or an isocyanurate ring formed on the surface of the first composite metal phosphate coating, an iron phosphate and a rare earth metal phosphate A second composite metal phosphate coating is provided.

  Forming a second composite metal phosphate coating comprising an allyl compound having a benzene ring or an isocyanurate ring, iron phosphate and a rare earth metal phosphate on the surface of the first composite metal phosphate coating; By providing a multilayer coating of the first composite metal phosphate coating and the second composite metal phosphate coating on the surface of the iron-based magnet alloy powder containing the rare earth element, a benzene ring is formed in the coating. Alternatively, an allyl compound having an isocyanurate ring can be contained. An allyl compound having a benzene ring or an isocyanurate ring has a plurality of allyl groups in its molecular structure and a benzene ring or isocyanurate ring that does not allow water to pass through. Protecting against rust prevents rusting and improves the salt water resistance of the magnet alloy powder.

  In the present invention, a single composite metal phosphate coating is not made to contain an allyl compound having a benzene ring or an isocyanurate ring, but a composite metal phosphate coating is formed in multiple layers, and a composite on the surface side is formed. The metal phosphate coating contains an allyl compound having a benzene ring or an isocyanurate ring. This is because if an allyl compound having a benzene ring or an isocyanurate ring is contained in a single composite metal phosphate coating, the phosphate treatment itself becomes insufficient, and the suppression of water permeation by the coating is sufficient. In addition, a new surface on which the composite metal phosphate coating is not formed appears on the surface of the magnet alloy powder due to the shearing force during kneading and molding, resulting in insufficient salt water resistance and This is because there is a high possibility that rust cannot be suppressed.

  The allyl compound applied to the present invention includes diallyl phthalate (DAP), diallyl isophthalate (DAI), triallyl isophthalate (TAI) having a benzene ring, diallyl tetrabromophthalate having an isocyanurate ring, and triallyl. An isocyanurate (TAIC) etc. can be mentioned. Although neither is specifically limited, it is preferable that the purity is 90% or more. If the purity of the allyl compound having a benzene ring or an isocyanurate ring is less than 90%, the influence of impurities becomes large, the formation of a film becomes difficult, and the salt water resistance is not improved. It tends to occur.

  An allyl compound having a benzene ring or an isocyanurate ring has a plurality of allyl groups in the molecular structure, and can be used alone or in combination from compounds having a benzene ring or an isocyanurate ring. .

  The addition amount of the allyl compound having a benzene ring or an isocyanurate ring needs to be in the range of 0.1% by mass to 5% by mass with respect to the powder mass of the magnet alloy powder for film formation. It is preferably in the range of 5% by mass to 3% by mass, and more preferably in the range of 1% by mass to 2% by mass. When the addition amount is less than 0.1% by mass, the addition effect is not sufficient, and the generation of rust cannot be suppressed. On the other hand, when the addition amount exceeds 5% by mass, the allyl compound having a benzene ring or an isocyanurate ring inhibits the formation of the second composite metal phosphate film, and as a result, the generation of rust is suppressed. Effect is not obtained.

  The average thickness of the second composite metal phosphate coating is in the range of 3 nm to 50 nm, preferably in the range of 5 nm to 45 nm, and more preferably in the range of 10 nm to 35 nm. When the average thickness of the second composite metal phosphate coating is less than 3 nm, the effect of adding an allyl compound having a benzene ring or an isocyanurate ring cannot be sufficiently obtained, and as a result, sufficient salt water resistance can be obtained. I can't. On the other hand, when this average thickness exceeds 50 nm, the amount of allyl compound having a benzene ring or an isocyanurate ring in the entire multilayer composite metal phosphate coating composed of the first and second composite metal phosphate coatings The salt water resistance is not sufficiently obtained.

  The average thickness of the first and second composite metal phosphate coatings as a whole is 28 nm or more, preferably in the range of 30 nm to 100 nm, and more preferably in the range of 35 nm to 70 nm. If the average thickness of the entire first and second composite metal phosphate coating is less than 28 nm, the surface of the magnet alloy powder cannot be sufficiently coated, and sufficient salt water resistance and mechanical strength cannot be obtained. On the other hand, if the average thickness exceeds 100 nm, the density of the magnet alloy powder cannot be increased, and the magnetic properties of the obtained rare earth magnet will be reduced. Also, for rare earth bonded magnets using the magnet alloy powder. The kneadability at the time of producing the composition is lowered, or the moldability of the magnet alloy powder and the composition for rare earth bonded magnet is lowered.

  Similarly, the average thickness of the second composite metal phosphate coating and the average thickness of the entire first and second composite metal phosphate coatings are also the same for the first and second composite metal phosphate coatings. It is the average value (5-point average value) of the film thickness of arbitrary 5 places obtained from the electron micrograph of the cross section of the iron-based magnet alloy powder containing the coated rare earth element.

  The iron-based magnet alloy powder containing the rare earth element of the present invention, in which the second composite metal phosphate coating is further formed on the surface of the first composite metal phosphate coating, is a raw material for the composition for rare earth bonded magnets. Alternatively, it is used as a raw material for rare earth compacted magnets. The composition for a rare earth bonded magnet using the iron-based magnet alloy powder containing the rare earth element of the present invention has good fluidity and moldability, and is an injection molding method, an injection compression molding method, an extrusion molding method, and an injection molding method. Good molding is possible by any molding method selected from press molding methods. Moreover, the iron-based magnet alloy powder containing the rare earth element of the present invention is excellent in salt water resistance. Therefore, by using the composition for rare earth bonded magnets of the present invention, it is possible to produce a rare earth bonded magnet having excellent salt water resistance and capable of suppressing rusting with good shape accuracy.

  Further, by compacting the iron-based magnet alloy powder containing the rare earth element of the present invention, a rare earth compacted magnet having an apparent density of 85% or more of the true density of the magnet alloy powder can be produced. The rare earth compacted magnet of the present invention also has high salt water resistance while having excellent magnetic properties as a rare earth magnet.

2. Method for Producing Iron-Based Magnet Alloy Powder Containing Rare Earth Element The iron-based magnet alloy powder containing the rare earth element provided with the multilayered composite metal phosphate coating of the present invention follows the iron-based magnet alloy coarse powder containing the rare earth element. It is manufactured by processing by this method.

(1) Formation of first composite metal phosphate coating In the present invention, an iron-based magnet alloy coarse powder containing a rare earth element is put into an organic solvent to which phosphoric acid is added, and the magnet alloy coarse powder is pulverized. Thus, a first composite metal phosphate coating containing iron phosphate and rare earth metal phosphate is formed on the surface of the iron-based magnet alloy powder containing rare earth elements. The iron-based magnet alloy crude powder containing rare earth elements obtained by the reduction diffusion method, the dissolution method, or the strip cast method usually contains a powder having an average particle size of more than 20 μm. In order to obtain good formability and sufficient magnetic anisotropy, such an iron-based magnet alloy coarse powder containing rare earth elements including a powder having an average particle size exceeding 20 μm has an average particle size in an organic solvent. It is necessary to grind to 8 μm or less, preferably 5 μm or less, and more preferably 1 μm to 3 μm. During the pulverization, the first composite metal phosphate coating is formed by stirring with phosphoric acid added. At this time, an oxide, composite oxide, phosphate, or hydrogen phosphate compound of one or more metals selected from Al, Zn, Mn, Cu, and Ca can be added together with phosphoric acid.

  The kind in particular of organic solvent is not restrict | limited, Any 1 type, or 2 or more types of mixtures, such as 2-methoxyethanol, isopropyl alcohol (IPA), ethanol, toluene, methanol, hexane, can be used. However, since methanol reacts quickly with phosphoric acid to be esterified to prevent the formation of a good film, it must be handled with care. In order to adjust the dissolution of the particle surface of the magnet alloy powder to an appropriate level, and when a metal component is added, in order to make the metal component easily generate metal ions, N, N- It is desirable to mix a polar solvent such as dimethylformamide or formamide. Moreover, in order to accelerate | stimulate melt | dissolution of the particle | grain surface of magnet alloy powder, you may mix water and an acid with an organic solvent. Among these, IPA can be suitably used because it is superior to other solvents in terms of cost and chemical stability (low boiling point).

Examples of phosphoric acid include orthophosphoric acid (H ₃ PO ₄ ) that reacts with a metal compound to form a metal phosphate, phosphorous acid (H ₃ PO ₃ ), hypophosphorous acid (H ₃ PO ₂ ), Pyrophosphate (H ₄ P ₂ O ₇ ), linear polyphosphoric acid, and cyclic metaphosphoric acid can be used. Moreover, ammonium phosphate, ammonium magnesium phosphate, etc. can also be used. These compounds may be used alone or in combination of a plurality of types, and are usually mixed with a chelating agent, a neutralizing agent or the like to form a treating agent. Of these, orthophosphoric acid exhibits preferable performance as a treating agent. This is because orthophosphoric acid is likely to react with the above metal compound and to form a protective film on the surface of the magnet alloy powder containing rare earth metal as a component. Phosphoric acid and its concentration are not limited, but phosphoric anhydride and phosphoric acid (orthophosphoric acid) 50% -99% aqueous solution, preferably phosphoric acid 75% -85% aqueous solution are readily available and easy to handle Therefore, it can be suitably used.

  The amount of phosphoric acid added is preferably in the range of 0.1 mol / kg to 2 mol / kg, preferably in the range of 0.15 mol / kg to 1.5 mol / kg, with respect to the powder mass of the magnet alloy coarse powder to be pulverized. More preferably, it is more preferable to set it as the range of 0.2 mol / kg-0.4 mol / kg. When the amount of phosphoric acid added is less than 0.1 mol / kg, the surface of the magnet alloy powder is not sufficiently coated, so that the salt water resistance of the magnet alloy powder is not improved. Heat is generated and the magnetic properties of the magnet alloy powder are extremely lowered. On the other hand, when it exceeds 2 mol / kg, the reaction with the magnet alloy powder occurs vigorously and the magnet alloy powder itself is dissolved.

  When the first composite metal phosphate coating further contains one or more metal components selected from Al, Zn, Mn, Cu, and Ca, oxides and composites of these metals together with phosphoric acid A metal compound such as an oxide, a phosphate, or a hydrogen phosphate compound is added. These metal compounds are ionized in an organic solvent, and react with the surface of the magnet alloy powder as the rare earth metal or iron, which is a component of the magnet alloy powder, elutes into the solvent. A film is formed by combining aluminum phosphate, zinc phosphate, manganese phosphate, copper phosphate, calcium phosphate, or phosphates of two or more metal components with the acid salt. For this reason, compared with the film which consists of iron and a rare earth element metal phosphate, it becomes possible to further improve the bond strength with a silicate film.

  The aluminum compound is not particularly limited as long as it is a source of aluminum ions and is soluble in an organic solvent. For example, aluminum acetate, aluminum sulfate, aluminum chloride, aluminum chloride ammonium, aluminum benzoate, aluminum carbonate, ethyl acetoacetate Aluminum, aluminum formate, aluminum hydroxide, aluminum nitrate, aluminum naphthenate, aluminum oleate, aluminum oxalate, aluminum oxide, aluminum phosphate, aluminum hydrogen phosphate, potassium aluminum chloride, aluminum stearate, aluminum sulfide, aluminum phthalocyanine, Aluminum tartrate or the like can be used. A particularly preferred aluminum compound is aluminum phosphate or aluminum hydrogen phosphate.

  The zinc compound is not particularly limited as long as it is a source of zinc ions and is soluble in an organic solvent. For example, zinc acetate, zinc sulfate, zinc chloride, zinc ammonium chloride, zinc benzoate, zinc carbonate, ethyl acetoacetate Zinc, zinc formate, zinc hydroxide, zinc nitrate, zinc naphthenate, zinc oleate, zinc oxalate, zinc oxide, zinc phosphate, zinc phosphate tetrahydrate, zinc hydrogen phosphate, zinc calcium phosphate, chloride Potassium zinc, zinc stearate, zinc sulfide, zinc phthalocyanine, zinc tartrate and the like can be used. Particularly preferred zinc compounds are zinc oxide, zinc phosphate tetrahydrate, or zinc hydrogen phosphate.

  The manganese compound is not particularly limited as long as it is a source of manganese ions and is soluble in an organic solvent. For example, manganese acetate, manganese sulfate, manganese chloride, manganese chloride, manganese benzoate, manganese carbonate, ethyl acetoacetate Manganese, manganese formate, manganese hydroxide, manganese nitrate, manganese naphthenate, manganese oleate, manganese oxalate, manganese oxide, manganese phosphate, manganese hydrogen phosphate, potassium chloride, manganese stearate, manganese sulfide, manganese phthalocyanine, Manganese tartrate or the like can be used. A particularly preferable manganese compound is manganese oxide or manganese hydrogen phosphate.

  The copper compound is not particularly limited as long as it is a source of copper ions and is soluble in an organic solvent. For example, copper acetate, copper sulfate, copper chloride, copper chloride ammonium, copper benzoate, copper carbonate, ethyl acetoacetate Copper, copper formate, copper hydroxide, copper nitrate, copper naphthenate, copper oleate, copper oxalate, copper oxide, copper phosphate, copper hydrogen phosphate, potassium copper chloride, copper stearate, copper sulfide, copper phthalocyanine, Copper tartrate or the like can be used. A particularly preferable copper compound is copper (I) oxide or copper hydrogen phosphate.

  The calcium compound is not particularly limited as long as it is a source of calcium ions and is soluble in an organic solvent. For example, calcium acetate, calcium sulfate, calcium chloride, calcium chloride ammonium, calcium benzoate, calcium carbonate, ethyl acetoacetate Calcium, calcium formate, calcium hydroxide, calcium nitrate, calcium naphthenate, calcium oleate, calcium oxalate, calcium oxide, calcium phosphate, calcium hydrogen phosphate, potassium chloride, calcium stearate, calcium sulfide, calcium phthalocyanine, calcium tartrate, etc. Can be used. A particularly preferable calcium compound is calcium oxide or calcium hydrogen phosphate.

  One or more metal oxides, composite oxides, phosphates, or hydrogen phosphate compounds selected from the metal components Al, Zn, Mn, Cu, and Ca are used for the particle size and surface area of the magnet alloy powder. The optimum amount is added according to the above, and the added amount is, for example, 0.01 mol / kg to 1 mol / kg with respect to the powder mass of the magnet alloy powder. When the addition amount is less than 0.01 mol / kg, the surface of the magnet alloy powder is not uniformly and sufficiently covered with the metal component, so the salt water resistance of the magnet alloy powder is not improved, whereas when it exceeds 1 mol / kg, Decrease in magnetic properties becomes remarkable, and performance as a magnet is reduced.

  When adding a metal component, the timing of addition is arbitrary, a method of dissolving in a solvent before pulverization, a method of adding once during pulverization, a method of gradually adding during pulverization, a method of dissolving in a solvent immediately after pulverization Etc. are used.

  Elements constituting magnetic alloy powders such as rare earth elements and iron eluted in solution form composite metal phosphates, or elements constituting magnetic alloy powders such as rare earth elements and iron eluted in solution are phosphorus. An acid salt is formed and reacts with the metal compound to form a composite metal phosphate, which coats the magnet alloy powder. In order to complete this reaction and form a film having a sufficient film thickness, the first composite metal phosphate film is formed depending on whether or not a metal compound is added or the type of metal compound added. In both the first stirring step for forming and the second stirring step for forming the second composite metal phosphate coating, the holding time for pulverization or stirring is 1 minute to 180 minutes. Preferably, the time is 3 minutes to 150 minutes, more preferably 5 minutes to 60 minutes.

  For pulverization or stirring, dry mechanical pulverization such as jet mill pulverization, or wet mechanical pulverization such as ball mill pulverization or medium stirring mill pulverization in an organic solvent such as alcohol can be used. In addition, when the iron-based magnet alloy coarse powder contains a powder having an average particle size exceeding 20 μm, the average particle size is 8 μm or less, preferably 5 μm or less, and more preferably 1 μm to 3 μm. Smash.

  In addition to the above-described method, the first composite metal phosphate coating is formed by adding phosphoric acid or phosphoric acid and a metal compound simultaneously with pulverization of the iron-based magnet alloy coarse powder containing rare earth elements. A coating treatment can be applied to the magnet alloy powder to be pulverized.

  Volatilize the organic solvent and excess treating agent used in the first composite metal phosphate coating treatment at a temperature of 100 ° C. or higher under reduced pressure with respect to the formed first composite metal phosphate coating. And heat treatment is performed to stabilize the coating. The temperature of the heat treatment is preferably 100 ° C to 200 ° C, and more preferably 120 ° C to 180 ° C. The treatment time is not particularly limited, but is usually 1 hour to 5 hours.

(2) Formation of second composite metal phosphate coating Forming a second composite metal phosphate coating comprising an allyl compound having a benzene ring or an isocyanurate ring, iron phosphate and a rare earth metal phosphate In order to achieve this, an iron-based magnet alloy powder containing a rare earth element on which a first composite metal phosphate coating has been formed and heat-treated with an allyl compound having a predetermined amount of a benzene ring or an isocyanurate ring The second composite metal phosphate coating can be uniformly formed on the surface of the first composite metal phosphate coating by adding and pulverizing it in an organic solvent to which phosphoric acid has been added.

  The allyl compound having a benzene ring or isocyanurate ring is not particularly limited, but it is preferable to use an allyl compound having a high-purity benzene ring or isocyanurate ring having a purity of 90% or more. If the purity is less than 90%, the influence of impurities becomes large and it becomes difficult to form a film, and not only the salt water resistance cannot be improved, but also the magnetic alloy powder tends to be oxidized and deteriorated.

  The addition amount of the allyl compound having a benzene ring or an isocyanurate ring is in the range of 0.1% by mass to 5% by mass, preferably 0.5% by mass to the mass of the magnetic alloy powder for film formation. It is in the range of 3% by mass, more preferably in the range of 1% by mass to 2% by mass. In addition, as an allyl compound having a benzene ring or an isocyanurate ring, a compound having a plurality of allyl groups in the molecular structure and having a benzene ring or an isocyanurate ring can be mixed and used.

  Similarly, the addition amount of phosphoric acid in the step of forming the second composite metal phosphate coating is set to 0.1 mol / kg to 2 mol / kg with respect to the powder mass of the magnet alloy powder forming the coating. Preferably, the range is 0.15 mol / kg to 1.5 mol / kg, more preferably 0.2 mol / kg to 0.4 mol / kg.

  Elements constituting magnets such as rare earth elements and iron eluted in organic solvents form phosphates and react with allyl compounds having a benzene ring or isocyanurate ring to have a benzene ring or isocyanurate ring A second composite metal phosphate coating in which allyl compounds are mixed is formed, and the second composite metal phosphate coating covers the magnet alloy powder. In order to complete this reaction and form a film having a sufficient film thickness, the holding time of stirring or grinding is 1 minute to 180 minutes, preferably 3 minutes to 150 minutes, more preferably 5 minutes to 60 minutes. .

  Also, in the step of forming the second composite metal phosphate coating, similarly to the pulverization or stirring, dry mechanical pulverization such as jet mill pulverization, ball mill pulverization or medium stirring mill pulverization in an organic solvent such as alcohol, etc. Wet mechanical grinding such as can be used.

  In order to make a composite metal phosphate coating composed of multiple layers obtained by forming a second composite metal phosphate coating after forming the first composite metal phosphate coating into a stable coating, The obtained magnet alloy powder is subjected to heat treatment at a temperature of 100 ° C. or higher under reduced pressure for stable formation of a film. The temperature of the heat treatment is preferably 100 ° C to 200 ° C, and more preferably 120 ° C to 180 ° C. Although there is no restriction | limiting in particular about processing time, Usually, it is preferable to set it as 1 hour-5 hours.

3. Composition for rare earth bonded magnet The composition for rare earth bonded magnet of the present invention is obtained by adding a resin binder to the iron-based magnet alloy powder containing the rare earth element of the present invention, in which the composite metal phosphate coating composed of the above-mentioned multiple layers is formed. As mentioned above, a thermoplastic resin or a thermosetting resin is blended. In the present invention, if desired, a lubricant, an ultraviolet absorber, a flame retardant, various stabilizers and the like can be added to the resin binder as other additives.

  The resin binder is a component that acts as a binder for the magnet alloy powder, and is a thermoplastic resin such as polyamide resin or polyphenylene sulfide resin, or epoxy resin, bis-maleimide triazine resin, unsaturated polyester resin, vinyl ester resin, curing Although thermosetting resins such as reactive silicone rubber can be used, it is particularly preferable to use thermoplastic resins.

  More specifically, examples of the thermoplastic resin include nylon 6, nylon 66, nylon 11, nylon 12, nylon 612, aromatic nylon, polymerized fatty acid polyamide resin, and modified nylon obtained by partially modifying these molecules. Polyamide resins such as: 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, ultra high 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, polyvinylidene chloride resin, polyvinyl acetate resin, polyvinyl alcohol resin, polyvinyl butyral resin, polyvinyl formal resin; methacrylic resin; polyvinylidene fluoride resin, polytrifluoroethylene chloride resin, tetrafluoroethylene resin Ethylene-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 resins, cellulose acetate resins, elastomers of these resins, and the like, random copolymers with these mono- and other types of monomers, block copolymers, graft copolymers, terminal by other substances Also includes group-modified products.

  It is desirable to use a thermoplastic resin having a low melt viscosity and low molecular weight within a range where desired mechanical strength can be obtained for the obtained rare earth bonded magnet. The shape of the thermoplastic resin is not particularly limited, such as a powder shape, a bead shape, or a pellet shape. However, it is desirable that the thermoplastic resin is in a powder shape because it is uniformly mixed with the magnet alloy powder in a short time.

  The blending amount of the thermoplastic resin is usually in the range of 5 to 100 parts by mass, preferably in the range of 5 to 50 parts by mass with respect to 100 parts by mass of the magnet alloy powder. When the blending amount of the thermoplastic resin is less than 5 parts by mass, the kneading resistance (torque) of the composition is increased or the fluidity is lowered, making it difficult to mold the magnet. On the other hand, when the amount exceeds 100 parts by mass, the ratio of the magnet alloy powder is reduced, and thus the rare-earth bonded magnet obtained from this composition cannot obtain desired magnetic properties.

  Examples of thermosetting resins include epoxy resins, phenol resins, bis-maleimide triazine resins, unsaturated polyester resins, vinyl ester resins, xylene resins, urea resins, melamine resins, thermosetting silicone resins, alkyd resins, furan resins. , Thermosetting acrylic resin, thermosetting fluororesin, urea resin, diallyl phthalate resin, polyurethane resin, silicon resin and the like.

  As the thermosetting resin, a two-component type is advantageous from the viewpoint of its handleability and pot life, and a thermosetting resin that can be cured at a temperature from room temperature to 200 ° C. after mixing the two components is used. Is preferred. The reaction mechanism may be a general addition polymerization type or a condensation polymerization type. Further, if necessary, a crosslinking reaction type monomer or oligomer such as peroxide may be added.

  These are not limited by the degree of polymerization or the molecular weight as long as they are in a reactable state, but in a final mixed state with a curing agent and other additives, the viscosity at 150 ° C. measured with an ASTM 100 rheometer is 500 Pa · s. Hereinafter, a thermosetting resin that is preferably 400 Pa · s or less, particularly preferably 100 to 300 Pa · s is used. When the viscosity in the final mixed state exceeds 500 Pa · s, it is not preferable because a significant increase in kneading torque and a decrease in fluidity are caused during molding, and it becomes difficult to mold a rare earth bonded magnet. On the other hand, when the viscosity is too small, the magnet alloy powder and the resin binder are easily separated during molding.

  The resin binder is preferably added in a ratio of 3 parts by mass to 50 parts by mass, more preferably in a ratio of 7 parts by mass to 30 parts by mass with respect to 100 parts by mass of the magnet alloy powder. More preferably, the ratio is from 20 parts by mass to 20 parts by mass. If the amount of the resin binder added is less than 3 parts by mass, the kneading torque will be significantly increased and the fluidity will be lowered, making it difficult to form a rare earth bonded magnet. On the other hand, if it exceeds 50 parts by mass, desired magnetic characteristics cannot be obtained in the obtained rare earth bonded magnet.

  A lubricant, an ultraviolet absorber, a flame retardant, various stabilizers, and the like can be added to the resin binder in the present invention. 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 Fatty acid amides such as stearic acid amide, ethylene bis stearic acid amide, ethylene bis lauric acid amide, distearyl adipic acid amide, ethylene bisoleic acid amide, dioleyl adipic acid amide, N-stearyl stearic acid amide; butyl stearate Fatty acid esters such as ethylene glycol, stearyl alcohol, and other alcohols; polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polyethers made from these modifications; polysiloxanes such as dimethylpolysiloxane and silicon grease; fluorine Fluorine compounds such as oils, fluorine grease, and fluorine-containing resin powders; silicon nitride, silicon carbide, magnesium oxide, alumina, silicon dioxide, molybdenum disulfide It includes inorganic compound powder. These lubricants may be used alone or in combination of two or more. The compounding quantity of a lubricant is 0.01 mass part-20 mass parts normally with respect to 100 mass parts of magnet alloy powder, Preferably, it is 0.1 mass part-10 mass parts.

  Examples of the ultraviolet absorber include benzophenone series such as phenyl salicylate; benzotriazole series such as 2- (2'-hydroxy-5'-methylphenyl) benzotriazole; oxalic acid anilide derivatives and the like.

  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-butyl In addition to hindered amine stabilizers such as bis (1,2,2,6,6-pentamethyl-4-piperidyl) malonate, antioxidants such as phenols, phosphites, and thioethers can be used. These stabilizers may be used alone or in combination of two or more. The blending amount of the stabilizer is usually in the range of 0.01 to 5 parts by mass, preferably 0.05 to 3 parts by mass with respect to 100 parts by mass of the magnet alloy powder.

  The mixing method is not particularly limited. For example, a blender such as a ribbon blender, tumbler, nauter mixer, Henschel mixer, super mixer, planetary mixer, or Banbury mixer, kneader, roll, kneader, single screw extruder, twin screw A kneader such as an extruder can be used.

The composition for rare earth bonded magnet of the present invention has high fluidity and excellent formability by using the iron-based magnet alloy powder containing the rare earth element of the present invention. The fluidity of the composition for rare earth bonded magnets can be measured by melt flow index measurement, measurement using an extrusion flow test mold, measurement using a spiral flow mold, or the like. In melt flow index measurement, a certain amount of resin is heated and pressurized at a specified temperature in a cylindrical container heated by a heater, the amount of resin discharged from the nozzle provided at the bottom of the container is measured, and its fluidity is measured. Is evaluated by the fluidity Q value (melt flow rate (MFR), unit: cm ³ / sec). The greater the fluidity Q value, the higher the fluidity of the rare earth bonded magnet composition and the better the injection moldability. Note that the measurement of fluidity is preferably based on JISK7210.

The composition for rare earth bonded magnets of the present invention exhibits a fluidity Q value of 0.40 cm ³ / sec or more, preferably 0.50 cm ³ / sec or more, more preferably 0.70 cm ³ / sec or more.

4). Rare earth bonded magnet The rare earth bonded magnet of the rare earth magnet of the present invention is, after the resin binder constituting the rare earth bonded magnet composition of the present invention is a thermoplastic resin, after being heated and melted at its melting temperature, It is obtained by molding into a desired shape. As the molding method at that time, various molding methods such as injection molding, extrusion molding, injection compression molding, injection press molding, transfer molding, etc., which are conventionally used for plastic molding, etc., should be applied. Among these, it is particularly preferable to use an injection molding method, an injection compression molding method, and an injection press molding method.

  On the other hand, when the resin binder constituting the rare earth bonded magnet composition of the present invention is a thermosetting resin, the shearing force is weak and the cooling function is prevented so that curing does not proceed due to shearing heat generation during mixing. It is preferable to use a mixing machine. Since the composition is agglomerated by mixing, the rare earth bonded magnet of the present invention is obtained by molding the agglomerated composition by an injection molding method, compression molding method, extrusion molding method, rolling molding method, transfer molding method, or the like. It is done.

  In the rare earth bonded magnet of the present invention, since the composition for rare earth bonded magnet of the present invention used for molding has high fluidity and excellent moldability, the rare earth bonded magnet which is a molded product in the molding process of the rare earth bonded magnet. No defects such as insufficient filling, flow mark, jetting, etc. occur. Here, the flow mark is a process in which the resin injected into the cavity is cooled by contacting the cavity surface and flowing through the cavity surface while being pushed by the subsequent resin while losing its viscosity. This refers to a phenomenon in which traces of annual rings crossing the direction remain on the surface of the molded product. Jetting means that the molten resin injected from the gate into the cavity at the time of injection molding is not filled from the end of the cavity, and the initial molten resin injected into the cavity is linear or meandering. In this way, the cavity is filled and cooled in the form of a long and slender thread, resulting in a site that is insufficiently fused with the subsequent resin, leaving linear or serpentine traces on the surface of the molded product. The phenomenon that ends up.

  The rare earth bonded magnet of the present invention thus obtained is not affected by salt water because it is difficult for defective portions to occur in the composite metal phosphate coating even under a high temperature environment. In a magnet alloy powder showing a nucleation type coercive force expression mechanism such as a samarium iron nitrogen (Sm-Fe-N) -based magnet, even when a defective region is generated in the composite metal phosphate coating, Although there was a problem that the coercive force is remarkably lowered, according to the present invention, such a problem is completely overcome.

  The salt water resistance (corrosion resistance) of the rare earth bonded magnet can be evaluated by a salt water resistance test such as a salt spray test method of JISZ2371: 2000. For example, after the molded rare earth bonded magnet is immersed in a 5% NaCl aqueous solution to half the width direction of the magnet, the inside of the tank is placed in a thermostatic bath set at 30 ° C. and left for 24 hours. The salt water resistance can be evaluated by observing the occurrence of the occurrence with a stereomicroscope.

5. Rare earth compacted magnet The rare earth compacted magnet of the present invention is produced by compacting the magnet alloy powder containing the rare earth element of the present invention by hot compression molding or hot pressing. The method for producing the rare earth consolidated magnet is not particularly limited as long as a high compressive force can be applied and the apparent density can be 85% or more of the true density. An apparent density of less than 85% is not preferable because the magnetic properties are lowered. In addition, since open pores serving as paths for oxygen and moisture, which are degradation factors of the magnet alloy powder, occur, the salt water resistance of the rare earth compacted magnet is lowered.

  In the magnetic alloy powder of the present invention, the composite metal phosphate coating contains an allyl compound having a benzene ring or an isocyanurate ring, and the allyl compound having a benzene ring or an isocyanurate ring is in its molecular structure. In addition to having allyl groups and water-permeable benzene rings or isocyanurate rings, the composite metal phosphate coating prevents contact between salt water and magnet alloy powder itself, which is a cause of deterioration of magnet alloy powder. Therefore, the rare earth compacted magnet of the present invention can also exhibit excellent salt water resistance.

  In addition to the excellent salt water resistance, the rare earth compacted magnet of the present invention improves its magnetic properties, particularly the coercive force of the magnet. In the case of samarium iron nitrogen (Sm-Fe-N) based magnet alloy powder, there is a possibility that decomposition or denitrification of the samarium iron nitrogen based compound may occur during consolidation. Non-magnetic composite metal phosphate coating exists uniformly and stably, preventing decomposition and denitrification of the samarium iron nitrogen-based alloy that constitutes the magnet alloy powder, and reducing the coercive force in the resulting rare earth compacted magnet Is prevented. The magnet alloy powder of the present invention exhibits high salt water resistance as it is, but, similarly to the technique described in Japanese Patent Application Laid-Open No. 2006-169618, a silicate film is formed on the surface of the composite metal phosphate film of the present invention. It is also possible to achieve higher salt water resistance by forming and sealing open pores that serve as routes for oxygen and moisture.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not limited at all by these Examples.

[Example 1]
(1) Component In any of the examples and comparative examples, a composition for a rare earth bonded magnet and a rare earth bonded magnet were manufactured using an iron-based magnet alloy powder containing a rare earth element. The following products or reagents were used as components of the rare earth bonded magnet composition. That is,
(A) As an iron-based magnet alloy powder containing a rare earth element, a samarium iron nitrogen (Sm-Fe-N) -based magnet alloy powder (manufactured by Sumitomo Metal Mining Co., Ltd.) having an average particle size of 3 μm,
(B) As an organic solvent, isopropyl alcohol (“2-propanol (IPA)”, manufactured by Kanto Chemical Co., Inc.)
(C) Among the components constituting the composite metal phosphate coating,
(C-1) As phosphoric acid, a phosphoric acid (orthophosphoric acid) 85% aqueous solution (“phosphoric acid”, manufactured by Kanto Chemical Co., Inc.)
(C-2) As a metal component, zinc oxide (3N5, manufactured by Kanto Chemical Co., Inc.)
(C-3) As an allyl compound having a benzene ring, diallyl phthalate (DAP; manufactured by Kanto Chemical Co., Inc., deer grade 1,> 97.0%) and triallyl isophthalate (TAI; manufactured by Kanto Chemical Co., Ltd.) Deer grade 1,> 97.0%), and
(D) Nylon 12 (“Daiamide (registered trademark) A1709P”, manufactured by Daicel Evonik Co., Ltd.) as a resin binder,
Each was used.

(2) Production of Rare Earth Bond Magnet Composition and Rare Earth Bond Magnet In Example 1, a rare earth bond magnet composition and a rare earth bond magnet were produced using an iron-based magnet alloy powder containing rare earth elements by the following method. did.

(2-1) Manufacture of iron-based magnet alloy powder containing rare earth elements After using an attritor crusher ("MA1SE", manufactured by Nihon Coke Kogyo Co., Ltd.), the atmosphere inside the container is replaced with nitrogen to form a nitrogen atmosphere. Into the container, 1 kg of isopropyl alcohol and 100 g (0.2 mol / kg) of 85% phosphoric acid aqueous solution are charged and mixed, and then 1.0 kg of samarium iron nitrogen-based magnet alloy coarse powder is charged, and the rotational speed of the rotor is set. The first pulverization was performed at 200 rpm for 1.0 hour to prepare a first slurry containing magnet alloy powder having an average particle size of 3 μm. The first slurry is filtered, and the filtrate is put into a mixer (“Henschel mixer”, manufactured by Nihon Coke Kogyo Co., Ltd.). While stirring, it is kept at 100 ° C. in vacuum and dried for 2 hours. did. Thereby, a magnet alloy powder coated with the first composite metal phosphate coating was obtained.

  Next, 1.0 g of diallyl phthalate and 100 g (0.2 mol / kg) of 85% aqueous solution of phosphoric acid are added to 1 kg of isopropyl alcohol, and then mixed with the first composite metal phosphate coating. The second pulverization (stirring) for 0.2 hours is performed using the same pulverizer at a rotational speed of the rotor of 50 rpm, and a magnetic alloy powder having an average particle diameter of 3 μm is used. 2 slurry was prepared. After separating and removing the solution from the second slurry, the surface of the magnet alloy powder coated with the first composite metal phosphate coating is subjected to heat treatment at a temperature exceeding 100 ° C. under reduced pressure and dried. And forming a second composite metal phosphate coating containing diallyl phthalate having a content of 0.2% by mass relative to the entire first and second coatings, thereby forming a multilayer having a total thickness of 30 nm. A magnetic alloy powder coated with a composite metal phosphate coating was obtained.

  Using a hermetic kneader (“LABO PLASTMILL”, manufactured by Toyo Seiki Seisakusho Co., Ltd.), the magnetic powder volume ratio of 60% was applied to 300 g of the magnetic alloy powder coated with the multilayered composite metal phosphate coating. Then, 24.3 g of nylon 12 was added, kneaded at 200 ° C. for 30 minutes, and further air-cooled to obtain a composition for a rare earth bonded magnet. Furthermore, the obtained composition was pulverized with a plastic pulverizer (manufactured by Hosokawa Micron Corporation) to obtain molding pellets.

  15 mm with an inline screw injection molding machine (“TL-50MGS” manufactured by Tanabe Kogyo Co., Ltd.) with a clamping pressure of 50 tons and a cylinder temperature of 230 ° C. and a mold temperature of 50 ° C. to 70 ° C. While applying an orientation magnetic field of 557 kA / m in the thickness direction, a cylindrical rare earth bonded magnet having a diameter of 10 mm × thickness of 15 mm was manufactured.

(3) Evaluation Each of the iron-based magnet alloy powder containing the rare earth element, the rare earth bonded magnet composition, and the rare earth bonded magnet was evaluated by the following method.

(3-1) Average thickness of composite metal phosphate coating Photograph of a cross section of a sample of the magnetic alloy powder coated with the first composite metal phosphate coating using an electron microscope, and the resulting electron micrograph From these, the film thicknesses at five arbitrary points for one powder were measured, and the average value of the five points was defined as the average thickness of the first composite metal phosphate coating. Similarly, a cross section of a sample of the magnet alloy powder coated with the first and second composite metal phosphate coatings was photographed using an electron microscope, and an arbitrary one of the powders was selected from the obtained electron micrograph. The five film thicknesses were measured, and the five-point average value was defined as the average thickness of the entire composite metal phosphate coating. Furthermore, the difference between the average thickness of the entire coating and the average thickness of the first composite metal phosphate coating was taken as the average thickness of the second composite metal phosphate coating. As the electron microscope, a transmission electron microscope (TEM; manufactured by Hitachi High-Technologies Corporation) was used.

(3-2) X-ray photoelectron spectroscopic analysis About an iron-based magnet alloy powder containing rare earth elements coated with a composite metal phosphate coating, an X-ray photoelectron spectroscopy (XPS) measuring device (“ESCALAB220i-XL, manufactured by VG Scientific, Inc.) ) Is used to check whether the iron (Fe metal) in the metal state, which is a constituent element of the magnet alloy powder, is present in the composite metal phosphate coating. It was evaluated that it was insufficient, and when there was no Fe metal, the coating treatment was sufficiently performed and it was evaluated that it was in a good state.

(3-3) Salt water resistance (corrosion resistance)
In a state in which the cylindrical rare earth bonded magnet obtained after molding is placed sideways, in a 5% NaCl aqueous solution, to a depth substantially equal to the radius of the cylindrical rare earth bonded magnet (the axial direction of the cylindrical rare earth bonded magnet). After immersion, the inside of the tank was placed in a thermostatic bath set at 30 ° C. and left for 24 hours. Thereafter, the presence or absence of rust was observed with a stereomicroscope, the case where there was no rust was evaluated as good, and the case where there was rust was evaluated as defective.

(3-4) Fluidity (Melt flow index measurement)
About molding pellets obtained by pulverizing the composition for rare earth bonded magnet, using a melt indexer (“G-02”, manufactured by Toyo Seiki Seisakusho Co., Ltd.), measurement temperature: 250 ° C. , Load: 21.6 kg, die swell: from the time required for a composition of a predetermined mass to pass through a diameter of 2.1 mm × thickness of 8 mm, its fluidity is determined by its fluidity Q value (melt flow rate (MFR), (Unit: cm ³ / sec). The greater the fluidity Q value, the higher the fluidity of the rare earth bonded magnet composition and the better the injection moldability.

(3-5) Injection moldability In the molding process of the rare earth bonded magnet, it was determined whether defects such as insufficient filling, flow mark, jetting, etc. occurred in the rare earth bonded magnet as a molded product. When these defects were not found, it was evaluated as good.

  The manufacturing conditions and evaluation results in Example 1 are shown in Table 1 and Table 2. In addition, about the following Examples 2-7 and Comparative Examples 1-6, it shows in Table 1 and Table 2 about the manufacturing conditions and evaluation result similarly.

[Example 2]
In the step of forming the second composite metal phosphate coating, 1.0 kg of triallyl isophthalate is substituted for 1 kg of isopropyl alcohol, instead of diallyl phthalate, and the content of the first and second coatings is 0.2. It is charged together with 100 g (0.2 mol / kg) of an 85% aqueous solution of phosphoric acid so as to be in mass%, and then magnetic alloy powder coated with the first composite metal phosphate film is charged, and the entire film is formed. A magnet alloy powder, a rare earth bonded magnet composition, and a rare earth bonded magnet were prepared and evaluated in the same manner as in Example 1 except that the thickness was 35 nm.

[Example 3]
In the step of forming the first composite metal phosphate coating, 1.0 g (0.1 mol / kg) of zinc oxide is added to the 85% aqueous solution of phosphoric acid, and the content of the first and second coatings is 1.0 mass. %, And in the step of forming the second composite metal phosphate coating, 1 kg of isopropyl alcohol is substituted with 5.0 g of triallyl isophthalate instead of diallyl phthalate, 2 is added together with 100 g (0.2 mol / kg) of an 85% aqueous solution of phosphoric acid so that the content with respect to the entire coating is 1.0% by mass, and then coated with the first composite metal phosphate coating. The magnet alloy powder, the rare earth bonded magnet composition, and the rare earth bonded magnet were obtained in the same manner as in Example 1 except that the magnet alloy powder was added and the total film thickness was 44 nm. To prepare a, it was carried out these evaluations.

[Example 4]
In the step of forming the second composite metal phosphate coating, 5.0 g of diallyl phthalate is added to 1 kg of isopropyl alcohol so that the content with respect to the entire first and second coating is 1.0 mass%. It is charged with 100 g (0.2 mol / kg) of 85% aqueous solution, and then the magnetic alloy powder coated with the first composite metal phosphate coating is charged, and the total film thickness is 42 nm. In the same manner as in Example 1, magnet alloy powder, a rare earth bonded magnet composition, and a rare earth bonded magnet were produced and evaluated.

[Example 5]
In the step of forming the second composite metal phosphate coating, 10 g of diallyl phthalate is added to 1 kg of isopropyl alcohol and 85% phosphoric acid so that the content of the first and second coatings is 2.0 mass%. Implemented with the exception that it was charged with 100 g (0.2 mol / kg) of the aqueous solution, and then the magnetic alloy powder coated with the first composite metal phosphate coating was charged and the total film thickness was 49 nm. In the same manner as in Example 1, magnet alloy powder, a rare earth bonded magnet composition, and a rare earth bonded magnet were produced and evaluated.

[Example 6]
In the step of forming the second composite metal phosphate coating, 85 g of phosphoric acid is added so that 25 g of diallyl phthalate is added to 1 kg of isopropyl alcohol and the content of the first and second coatings is 5.0% by mass. It was carried out except that it was charged with 100 g (0.2 mol / kg) of the aqueous solution, and then the magnetic alloy powder coated with the first composite metal phosphate coating was charged to set the total film thickness to 75 nm. In the same manner as in Example 1, magnet alloy powder, a rare earth bonded magnet composition, and a rare earth bonded magnet were produced and evaluated.

[Example 7]
In the step of forming the second composite metal phosphate coating, 5.0 g of diallyl phthalate and 5.0 g of triallyl isophthalate are added to 1 kg of isopropyl alcohol and the respective contents of the first and second coatings are 1. It was charged with 100 g (0.2 mol / kg) of 85% phosphoric acid aqueous solution so as to be 0% by mass, and then magnetic alloy powder coated with the first composite metal phosphate coating was charged. A magnet alloy powder, a rare earth bonded magnet composition, and a rare earth bonded magnet were produced and evaluated in the same manner as in Example 1 except that the film thickness was 48 nm.

[Comparative Example 1]
Using a pulverizer, the atmosphere inside the container was replaced with nitrogen to form a nitrogen atmosphere, and then 1 kg of isopropyl alcohol and 100 g (0.2 mol / kg) of 85% aqueous phosphoric acid solution were charged into the container and mixed. Thereafter, 1 kg of samarium-iron-nitrogen-based magnet alloy powder was charged and pulverized for 1.0 hour at a rotor rotation speed of 200 rpm to prepare a magnet alloy powder slurry having an average particle diameter of 3 μm. This slurry is filtered, and the filtrate is put into a mixer, and is stirred and kept at 100 ° C. in a vacuum and dried for 2 hours. Only by a single composite metal phosphate film having a film thickness of 20 nm. A coated magnet alloy powder was obtained. Thereafter, in the same manner as in Example 1, a rare earth bonded magnet composition and a rare earth bonded magnet were obtained and evaluated.

[Comparative Example 2]
Using a pulverizer, the atmosphere inside the container was replaced with nitrogen to form a nitrogen atmosphere, and then 1 kg of isopropyl alcohol, 2.5 g of diallyl phthalate were contained in the container, and the content with respect to the entire coating was 0.5 mass%. In this way, it was added together with 100 g (0.2 mol / kg) of 85% aqueous phosphoric acid solution, and then 1 kg of samarium iron nitrogen-based magnet alloy powder was added, and the rotor rotation speed was 200 rpm and pulverized for 1.0 hour. A magnetic alloy powder slurry having an average particle diameter of 3 μm was prepared. This slurry is filtered, and the filtrate is put into a mixer, and is stirred and kept at 100 ° C. in a vacuum and dried for 2 hours. Only by a single composite metal phosphate film having a film thickness of 20 nm. A coated magnet alloy powder was obtained. Thereafter, in the same manner as in Example 1, a rare earth bonded magnet composition and a rare earth bonded magnet were obtained and evaluated.

[Comparative Example 3]
Into 1 kg of isopropyl alcohol, 25 g of diallyl phthalate is added together with 100 g (0.2 mol / kg) of 85% aqueous phosphoric acid so that the content of the first and second coatings is 5.0% by mass, Thereafter, 1 kg of samarium-iron-nitrogen-based magnet alloy powder was added, and the magnet alloy powder, the composition for rare earth bonded magnet, and the rare earth bonded magnet were the same as in Comparative Example 2 except that the total film thickness was 25 nm. These were evaluated.

[Comparative Example 4]
1 kg of isopropyl alcohol, instead of diallyl phthalate, 25 g of triallyl isophthalate are added together with 100 g (0.2 mol / kg) of 85% aqueous phosphoric acid so that the content of the coating is 5.0% by mass. Then, 1 kg of samarium iron nitrogen-based magnet alloy powder was added, and in the same manner as in Comparative Example 2 except that the total film thickness was 27 nm, the magnet alloy powder, the rare earth bonded magnet composition, and A rare earth bonded magnet was produced and evaluated.

[Comparative Example 5]
In the step of forming the second composite metal phosphate coating, 0.25 g of diallyl phthalate is added to 1 kg of isopropyl alcohol so that the content with respect to the entire first and second coatings is 0.05 mass%. Except that 100 g (0.2 mol / kg) of 85% aqueous solution was added, and then magnet alloy powder coated with the first composite metal phosphate coating was added, and the total film thickness was 22 nm. In the same manner as in Example 1, magnet alloy powder, a rare earth bonded magnet composition, and a rare earth bonded magnet were produced and evaluated.

[Comparative Example 6]
In the formation process of the second composite metal phosphate coating, 35 g of diallyl phthalate is added to 1 kg of isopropyl alcohol, and phosphoric acid is 85% so that the content with respect to the entire first and second coating is 7.0% by mass. Implementation with the exception that it was charged with 100 g (0.2 mol / kg) of the aqueous solution, and then the magnetic alloy powder coated with the first composite metal phosphate coating was charged to set the total film thickness to 120 nm. In the same manner as in Example 1, magnet alloy powder, a rare earth bonded magnet composition, and a rare earth bonded magnet were produced and evaluated.

"Evaluation"
In Examples 1 to 7, the first composite metal phosphate coating is formed on the surface of the samarium iron nitrogen (Sm—Fe—N) -based magnet alloy powder, and the surface of the first composite metal phosphate coating is further formed. A second composite metal phosphate coating containing an allyl compound having a benzene ring or an isocyanurate ring is formed, and a magnetic alloy powder coated with such a multilayer composite metal phosphate coating is used. Then, a rare earth bonded magnet composition was prepared, and further, this composition was injection molded to obtain a rare earth bonded magnet.

  The compositions for rare earth bonded magnets of Examples 1 to 7 have an improved fluidity Q value compared to Comparative Example 1 corresponding to a conventional product using a magnet alloy powder coated with only one composite metal phosphate coating. In addition, it is understood that the moldability is improved and the moldability is improved.

  In Comparative Example 1, the presence of metallic iron (Fe metal), which is a constituent element of the magnet alloy powder, was observed in the composite metal phosphate coating on the surface by XPS surface analysis. In the magnetic alloy powder coated with the multi-layered composite metal phosphate coating of ˜7, the surface of the composite metal phosphate coating is free of Fe metal by XPS surface analysis. It is understood that it was sufficient.

  Furthermore, in the salt water immersion test, almost no rust is observed in the magnetic alloy powder coated with the multilayered composite metal phosphate coating of Examples 1 to 7, and the effect of suppressing the occurrence of rust is the benzene ring. It is understood that the allyl compound is improved by the addition of diallyl phthalate or triallyl isophthalate.

  On the other hand, in Comparative Examples 1 to 4 in which the phosphate treatment was performed only once, the fluidity Q value was lowered regardless of the presence or absence of addition of diallyl phthalate or triallyl isophthalate. From the surface analysis results, Fe metal was detected on the surface of the coating, and as a result of the salt water immersion test, a lot of rust was observed. This is because in the single-layer composite metal phosphate coating obtained in Comparative Examples 1 to 4, even if diallyl phthalate or triallyl isophthalate is added, the phosphate treatment itself is insufficient and depends on the coating. The ability to suppress the permeation of water was weak and the surface of the magnetic alloy powder could not be protected from salt water. Furthermore, the surface of the magnetic alloy powder was subjected to a composite metal phosphate due to the shearing force during kneading and forming. It is considered that rust could not be suppressed due to the appearance of a new surface on which no salt film was formed.

  On the other hand, in Comparative Example 5 and Comparative Example 6, although a multilayered composite metal phosphate coating was formed, the amount of diallyl phthalate added deviated from the preferred range with respect to the total mass of the magnet alloy powder. In Comparative Example 5 in which the amount of diallyl phthalate added was small relative to the powder mass of the magnetic alloy powder to be coated, the effect of adding diallyl phthalate was not sufficient and rust could not be suppressed. On the other hand, in Comparative Example 6 in which the amount of diallyl phthalate used is too large, diallyl phthalate is considered to have inhibited the formation of the second composite metal phosphate coating, and a sufficient structure that can suppress water permeation by the coating It is considered that the formation of a composite metal phosphate coating that can protect the surface of the magnet alloy powder from salt water is insufficient, and as a result, rust cannot be suppressed.

Claims (11)

An iron-based magnet alloy powder containing rare earth elements,
The first composite metal phosphate coating containing iron phosphate and rare earth metal phosphate formed on the surface of the magnet alloy powder, and the benzene formed on the surface of the first composite metal phosphate coating An allyl compound having a ring or an isocyanurate ring, and a second composite metal phosphate coating containing iron phosphate and a rare earth metal phosphate,
The addition amount of the allyl compound added to the second composite metal phosphate coating is 0.1% by mass to 5% by mass with respect to the total mass of the magnet alloy powder.
An iron-based magnet alloy powder containing a rare earth element.   The iron-based magnet alloy powder containing a rare earth element according to claim 1, wherein the average thickness of the entire first and second composite metal phosphate coatings is 28 nm or more.   The iron-based magnet alloy powder containing rare earth elements according to claim 1 or 2, wherein the average particle size is 8 µm or less.   The rare earth element according to any one of claims 1 to 3, wherein the first composite metal phosphate coating further contains at least one selected from Al, Zn, Mn, Cu, and Ca as a metal component. Containing iron-based magnet alloy powder. An iron-based magnet alloy coarse powder containing a rare earth element is put into an organic solvent to which phosphoric acid is added, and the magnet alloy coarse powder is pulverized to form phosphoric acid on the surface of the iron-based magnet alloy powder containing the rare earth element. Forming a first composite metal phosphate coating comprising iron and a rare earth metal phosphate;
Separating and recovering the magnet alloy powder from the slurry containing the magnet alloy powder, and subjecting the magnet alloy powder to a heat treatment of 100 ° C. or higher under reduced pressure;
By introducing the magnet alloy powder after the heat treatment into an organic solvent to which an allyl compound having a benzene ring or an isocyanurate ring and phosphoric acid are added, and pulverizing the magnet alloy powder, Forming a second composite metal phosphate coating comprising the allyl compound, iron phosphate and rare earth metal phosphate on the surface of the first composite metal phosphate coating;
Separating and recovering the magnet alloy powder from the slurry containing the magnet alloy powder provided with the first and second composite metal phosphate coatings, and subjecting the magnet alloy powder to a heat treatment at 100 ° C. or higher under reduced pressure; ,
A method for producing an iron-based magnet alloy powder containing a rare earth element.   The organic solvent used in the step of forming the first and second composite metal phosphate coatings is selected from N, N-dimethylformamide, formamide, 2-methoxyethanol, ethanol, methanol, and isopropyl alcohol. The manufacturing method of the iron-type magnet alloy powder containing the rare earth elements of Claim 5 which is a seed | species or more.   In the step of forming the first and second composite metal phosphate coatings, the phosphoric acid is added to the magnet alloy powder in an amount of 0.1 mol / kg to 2 mol / kg per mass. The manufacturing method of the iron-type magnet alloy powder containing the rare earth elements of Claim 5 or 6 to add.   In the process of forming a 1st composite metal phosphate film, the metal component containing 1 or more types chosen from Al, Zn, Mn, Cu, and Ca is added in any one of Claims 5-7. Of producing an iron-based magnet alloy powder containing rare earth elements.   It is a composition for rare earth bond magnets containing the iron-based magnet alloy powder containing rare earth elements and the resin binder which consists of a thermoplastic resin or a thermosetting resin, Comprising: The said magnet alloy powder is any of Claims 1-4. A composition for a rare earth bonded magnet, which is an iron-based magnet alloy powder containing the rare earth element described above.   A rare earth bonded magnet formed by molding the composition for a rare earth bonded magnet according to claim 9.   It is a rare earth compacted magnet comprised by the iron-based magnet alloy powder containing the consolidated rare earth element, Comprising: The said magnet alloy powder is the iron-based magnet alloy powder containing the rare earth element in any one of Claims 1-4. There is a rare earth compacted magnet.