JPH07201620A - R-fe-b based bond magnet and production thereof - Google Patents

Abstract

PURPOSE:To provide an R-Fe-B based bond magnet, and its production method, having such composition as the plating liquid and the like can be prevented from entering into a porous R-Fe-B based bond magnet and being left thereat and a plating layer of Ni, for example, is formed efficiently thus enhancing the corrosion resistance and heat resistance significantly. CONSTITUTION:A porous R-Fe-B based bond magnet is impregnated with an inorganic substance, e.g. glass, or a resin to fill the pores of magnet and then it is subjected to surface polishing, e.g. barrel polishing or sand blasting, thus reforming the surface while sustaining the impregnation effect. Even if it is subjected to direct electrolytic plating or electroless plating, deterioration of corrosion resistance due to exfoliation of plating layer caused by internal rusting can be prevented because intrusion of toxic plating liquid or cleaning liquid is prevented. Consequently, a general plating bath having high filming efficiency, e.g. Watt bath, can be employed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved R-Fe-B type bonded magnet called a rubber magnet or a plastic magnet having various shapes such as a ring shape and a disk shape and a method for producing the same, and particularly to a glass. Mass production of plating layer such as Ni plating with significantly improved corrosion resistance and adhesion by using a plating solution that can be efficiently plated with a Watts bath, etc. The present invention relates to a well-formed R-Fe-B based bonded magnet and a method for manufacturing the same.

[0002]

2. Description of the Related Art Today, there are known bonded magnets called rubber magnets or plastic magnets, from conventional isotropic bonded magnets to anisotropic bonded magnets, and ferrite-based bonded magnets to rare-earth bonded magnets having a higher magnetic force. The performance of the R-Fe-B-based magnetic material is improved from Sm-Co-based magnetic material, and the sintered magnet has a maximum energy product of 50 MGOe or more and exhibits high magnetic characteristics. High performance has been achieved for bonded magnets.

The R-Fe-B system bonded magnet has a required R-
A melting and crushing method of melting an Fe-B alloy and crushing it after casting (JP-A-60-63304, JP-A-60-11907).
No. 01), direct reduction diffusion method for directly obtaining powder by Ca reduction (JP-A-59-219404, JP-A-60-7794).
No. 3), a quenching alloy method in which a required R-Fe-B alloy is melted, a ribbon foil is obtained with a jet caster, and this is crushed and annealed, and a required R-Fe-B alloy is heated in hydrogen. Various R-Fe-B based magnetic material powders obtained by various production methods such as a method of decomposing and recrystallizing (HDDR method) (JP-A-1-132106, JP-A-2-4901) are used. However, there is a problem that it easily rusts because its composition contains a component phase that is extremely easy to oxidize and a large amount of Fe. A resin layer of various compositions is applied to the surface by electrodeposition coating, spraying, dipping, impregnation, etc. (For example, Japanese Patent Laid-Open No. 1-16
6519, JP-A-1-245504).

In the conventional resin coating method, for example, in the case of a spray method, in the case of a ring shape, there is a problem that the loss of the coating material is large, the number of steps is large because the inside and the outside need to be reversed, and the uniformity of the film thickness is poor. It was Further, in the electrodeposition method, although the film thickness is uniform, repair of the electrode portion, that is, touch-up is required, and the electrodes are attached to the electrodes one by one, which requires a lot of man-hours and is not suitable for small articles. With the dipping method, it is difficult to obtain a uniform coating film with a constant film thickness due to sagging, etc. Also, pores are not filled up sufficiently with a porous bonded magnet, and swelling during drying and sticking between products There is.

[0005]

[Problems to be Solved by the Invention] Considering mass productivity,
Applying metal plating, which is performed with a sintered type R-Fe-B magnet (Japanese Patent Laid-Open No. 60-54406, Japanese Patent Laid-Open No. 62-62406).
No. 120003), but when metal plating is applied to a porous bonded magnet, the immersed surface cleaning agent or plating solution penetrates into the magnet and remains, so that metal plating is impossible due to melting damage or rusting.

Therefore, is it possible to select a plating solution that is harmless even if it penetrates into and remains in the porous bonded magnet (JP-A-4-27).
No. 6092) and plating after applying a base coating (JP-A-3-11714, JP-A-4-276095).
No.) method has been proposed. However, it is difficult to adjust the pH of the plating solution and completely render it harmless, and the plating bath is not good in film formation efficiency. Further, there is a contradiction that the variation in the thickness of the underlayer becomes an unstable factor of the plating layer, and if the undercoating with a sufficient thickness is applied, the plating layer on the surface becomes unnecessary. A plating bath having a specific composition has been proposed as a method for performing Ni plating with good film formation efficiency on an R-Fe-B based bonded magnet (Japanese Patent Laid-Open No. 4-99192). May cause rusting.

According to the present invention, a plating solution, a cleaning solution, etc. can be prevented from invading and remaining in a porous R-Fe-B based bonded magnet, and a plating layer such as Ni plating can be efficiently formed.
R with a structure that can significantly improve corrosion resistance and heat resistance
It is intended to provide a —Fe—B based bonded magnet and a method for manufacturing the same.

[0008]

Means for Solving the Problems The inventor has found that a plating solution, a cleaning solution, or the like penetrates into a porous R-Fe-B based bonded magnet,
As a result of various studies on the structure of a magnet that can prevent the residue from remaining, the magnet is impregnated with an inorganic material such as glass or a resin, and the holes of the magnet are impregnated with an inorganic material such as glass or a resin. By performing surface polishing treatment such as treatment, the surface can be modified while maintaining the impregnation effect, and even if it is directly electroplated or electroless plated, harmful plating solution and cleaning solution are prevented from entering. Therefore, the inventors have found that there is no deterioration in corrosion resistance such as rusting from the inside and peeling of the plating layer, and a general plating bath such as a Watt bath having a high film formation efficiency can be used, and the present invention has been completed.

That is, the present invention has a structure in which the inorganic material such as glass or the resin layer on the surface is removed while the inorganic material such as glass or the resin impregnated in the pores of the R—Fe—B system bonded magnet is removed, and further, This is an R-Fe-B based bonded magnet in which a plating layer is directly formed on the bare surface of the magnet material itself.
In addition, in the above structure, an R—Fe—B based bonded magnet characterized in that the porosity of the surface layer of the magnet is 1% or less is also proposed.

The present invention is characterized in that the porosity of the surface layer of the bonded magnet is 3% or less. The porosity is the porosity of the pores which are communicated from the surface of the porous bonded magnet to the inside of the magnet. It is the ratio of the volume, and in the R—Fe—B based bonded magnet, the porosity when molded by the compression molding method is 5 to 20%. Also, when the porosity exceeds 3%, the plating solution penetrates inside and remains there to deteriorate the corrosion resistance and heat resistance.
The porosity is preferably 3% or less.

Further, according to the present invention, the R-Fe-B based bonded magnet is impregnated with a resin to impregnate the holes of the magnet with an inorganic material such as glass or a resin, and the surface is covered with an inorganic material such as glass or a resin layer. The R-Fe-B based bonded magnet to be formed is impregnated with an inorganic substance such as glass or a resin to impregnate pores of the magnet with the inorganic substance such as glass or a resin, and an inorganic substance such as glass or a resin layer is formed on the surface. After that, a plating layer is formed on the inorganic material such as glass or the resin layer. R-Fe
-B type bond magnet is impregnated with an inorganic material such as glass or a resin to impregnate pores of the magnet with the inorganic material such as glass or a resin, and then the inorganic material such as glass or a resin layer formed on the surface is removed. An R-Fe-B based bonded magnet is impregnated with an inorganic substance such as glass or a resin to impregnate pores of the magnet with the inorganic substance such as glass or a resin, and then an inorganic substance such as glass or a resin layer formed on the surface thereof. Remove and further form a plating layer on the magnet surface. The plating layer forming means is electroless plating. The plating layer forming means is electrolytic plating. The plating layer is formed by electroless plating. After that, a method for producing an R—Fe—B based bonded magnet is further characterized, in which a plating layer is further formed by an electrolytic plating method.

In the present invention, the R—Fe—B based bonded magnet is intended for both isotropic and anisotropic bonded magnets.
For example, in the case of compression molding, a thermosetting resin, a coupling agent, a lubricant, etc. are added and kneaded to the magnetic powder of the required composition and properties, and then the mixture is compression-molded and heated to obtain a resin which is cured by injection molding. In the case of extrusion molding or rolling molding, it is obtained by kneading a magnetic powder with a thermoplastic resin, a coupling agent, a lubricant, etc., and then molding by any of injection molding, extrusion molding, and rolling molding. The R-Fe-B based magnetic material powder is a melting and pulverizing method in which a required R-Fe-B based alloy is melted and crushed after casting, a direct reduction diffusion method for directly obtaining a powder by Ca reduction, a required R- A quenching alloy method in which a Fe-B-based alloy is melted and a ribbon foil is obtained with a jet caster, and the ribbon foil is crushed and annealed. ,
Mechanical alloying method in which the required raw material metal is pulverized, then finely pulverized by mechanical alloying and heat treated, and a method of decomposing and recrystallizing the required R-Fe-B alloy by heating in hydrogen (HDDR method) Isotropic and anisotropic powders obtained by various production methods such as can be used. In addition, the binder is 6PA, 12PA, PPS, PB in injection molding.
PVC, NBR, CPE, NR, Hypalon, etc. for T, EVA, etc.
For the compression molding, epoxy resin, DAP, phenol resin, etc. can be used, and a known metal binder can be used if necessary. Further, as the auxiliary material, a lubricant that facilitates molding, a binder of a resin and an inorganic filler, a coupling agent such as a silane-based or titanium-based coupling agent, and the like can be used.

In the present invention, the inorganic material such as glass to be impregnated or the resin includes inorganic water glass, various low melting point metals and metal powders, content, or organic methacrylic acid ester, epoxy resin, polyacetylene, polyaniline. A single resin or a composite resin such as can be used.

In the present invention, the impregnation treatment method includes dipping in an inorganic material such as glass or a resin, or housing a bond magnet in a closed container and evacuating the inside of the container before immersing in an inorganic material such as glass or a resin. Then, pressurize, evacuate the inside of the container and then immerse it in an inorganic material such as glass or resin, evacuate again, and then pressurize, immerse in an inorganic material such as glass or resin in the container, evacuate, and then add Press, soak in an inorganic material such as glass or resin in a container and evacuate, evacuate the inside of the container and then immerse in an inorganic material or resin such as glass, evacuate the inside of a container to an inorganic material or resin such as glass It can be impregnated by a procedure such as dipping and vacuuming again. Further, for the drying and curing treatments after the impregnation treatment, a means for heating in air, in an inert gas or in vacuum can be used. Furthermore, in order to impregnate large pores, it is possible to insert metal powder, pigment, etc. into the barrel and rub it against the surface of the bond magnet, or use a method such as tapping to make the impregnation treatment more effective. Is possible.

In the present invention, as a method of removing the inorganic material such as glass or the resin layer formed on the surface of the magnet after the impregnation treatment, the surface impregnation treatment such as barrel polishing treatment or sandblasting treatment is performed to maintain the impregnation effect. The surface can be modified as it is. As the barrel polishing, a general rotary barrel, a centrifugal rotary polishing method, a vibrating barrel polishing method, or the like can be adopted.As the sand blast, a commonly used surface polishing method with polishing sand, and an object to be polished are stored in a container. It is possible to employ a rotary sandblast method or the like in which the container is put into a container and sandblasted while rotating the container. By the above surface polishing treatment, not only the inorganic material such as glass or resin layer formed on the magnet surface by the impregnation treatment is removed, but also the surface oxidized layer of the magnet is removed,
The surface of the active R-Fe-B magnetic powder can be obtained,
It is possible to form a plating layer having excellent corrosion resistance and adhesiveness.

In the present invention, as the electrolytic plating method, at least one base metal selected from Ni, Cu, Sn, Co, Zn, etc. or an alloy layer thereof, B, S, P is used.
The plating method which may be contained is preferable. The plating thickness is 50 μm or less, preferably 20 μm or less. The plating bath preferably has a pH of 5.6 or higher. In the present invention, since the above-mentioned impregnation treatment works effectively, plating can be performed by a general Watt bath, and a plating layer having sufficient adhesion, corrosion resistance and heat resistance can be obtained.

Particularly, as the Ni plating bath and the plating method, it is preferable to perform the steps of washing → electrical Ni plating → washing → drying. A bath containing no chloride ion in the Ni plating bath solution is preferable, and nickel sulfate, sodium sulfate, Magnesium sulfate, ammonium citrate or sodium citrate,
Six components of cobalt sulfate and boric acid are appropriately selected according to the composition of the R-Fe-B based bonded magnet, the component A (nickel sulfate) is set to 100 g / l to 150 g / l, the component B (sodium sulfate), The relationship of A = B + C with the C component (magnesium sulfate) is desirable, and the composition ratio of B and C is preferably B: C = 3 to 7: 7 to 3. Ammonium citrate or sodium citrate is 20 to 2 of the A component.
5% is the optimum composition range, and 1/3 to 1/1 of this component
Two amounts of boric acid are suitable as an addition amount at the time of building bath. Cobalt sulfate is preferable because 1 to 5% of the component A has the effect of improving the adhesiveness. The pH is adjusted with ammonia water, the pH is used in the range of 5.4 to 6.8, and the bath temperature at room temperature is preferable.

For Ni plating, the above-mentioned plating bath is used, and a required current is applied to the anode plate by using a nickel chip containing S or further Co component to perform electric Ni plating. The Ni component in the Ni plating bath is melted. In order to stabilize the output, it is desirable to use an esland nickel tip containing S in the electrode. Various baths can be used in the plating bath depending on the shape of the bonded magnet, and particularly in the case of a ring-shaped bonded magnet, barrel plating treatment is desirable.

In the present invention, the electroless plating method is preferably a plating method in which B, S, and P may be contained in Ni, Cu, Sn, Co, etc., and the plating thickness is 10 μm.
m or less, and the plating bath preferably has a pH of 5 to 9.

[0020]

The present invention is characterized in that an R-Fe-B based bonded magnet is impregnated with an inorganic substance such as glass or a resin to impregnate the holes of the magnet with the inorganic substance such as glass or a resin. Is filled with harmful plating solution,
Invasion of a cleaning liquid is prevented, electroless plating is possible on an inorganic material such as impregnated glass or a resin layer, and a corrosion resistant coating with significantly improved corrosion resistance and adhesion is obtained. Further, after the above-mentioned impregnation treatment, barrel polishing treatment, surface polishing treatment such as sandblasting treatment is performed to remove inorganic substances such as glass or resin formed on the surface, so that the pores of the magnet are sealed. The surface can be modified while retaining the above, and even if it is directly electroplated or electroless plated, harmful plating solution and cleaning solution are prevented from invading. A corrosion-resistant coating having significantly improved corrosion resistance and adhesion can be obtained without deterioration of corrosion resistance such as. The plating layer can also have a two-layer structure in which electroless plating is performed on top of electroless plating. In addition, the holes are sealed to prevent harmful plating solution and cleaning solution from entering, making it a common and effective solution for Watts baths. A plating bath with good film efficiency can be used.

[0021]

【Example】

Example 1 Nd12at%, Fe77at% produced by the ultra-quenching method,
Average particle size 15 consisting of B6 at% and Co5 at%
2 wt% of epoxy resin was added to 0 μm alloy powder, and the mixture was kneaded and compression-molded at a pressure of 7 Ton / cm ² , then 15
Heat treated at 0 ℃ for 1 hour, outer diameter 28 × inner diameter 25 × height 5
A ring-shaped bonded magnet was manufactured. The magnet characteristics of the obtained bonded magnet were Br 6.9 kG, (BH) max 9.
8MGOe, iHc9.5kOe, Hr3.5kOe,
The density was 5.95 g / cm ³ . The obtained 20 magnets were immersed in a 20 wt% sodium silicate aqueous solution for 5 minutes and then heated at 150 ° C. for 1 hour to remove water and cure. Then, 60% of the barrel volume of tetra-shaped media having a side length of about 3 mm was put into a rotary barrel having a volume of 5 liters, and surface polishing was performed at a rotation speed of 20 rpm for 10 minutes. Then, after washing with water for 2 to 3 minutes, electric Ni plating was performed in the barrel. The film thickness of the Ni plating was 20 μm on the inner diameter side and 30 μm on the outer diameter side. The electric Ni plating conditions are as follows. Polar current density 1 A / dm ² , plating time 3.5 hours Plating solution composition Ni sulfate 100 g / l, sodium sulfate 50 g / l, magnesium sulfate 50 g / l, ammonium citrate 25 g / l, sulfuric acid Co 2 g / l, boric acid 12 g /
1, bath temperature 20 ° C, pH 6.6

Comparative Example The ring-shaped bonded magnet obtained by the same method as in Example 1 was directly subjected to the same electric Ni plating treatment as in Example 1 without dipping or polishing. Table 1 shows the magnet characteristics after the Ni plating treatment. Table 1 also shows the porosity of the magnet before Ni plating. The porosity was measured by the oil content calculated from the weight change by putting a magnet in oil and sucking it in vacuum (0.1 Torr or less) for 10 minutes. Hk is 0.
It shows Hc at 9Br, and if this value is low, the squareness ratio decreases,
That is, it represents the degree of deterioration due to the plating solution.

Example 2 In Example 1, except that the dipping treatment and the hardening treatment were performed by dipping in a liquid in which 20% of a water-soluble acrylic resin component was dissolved in pure water for 5 minutes and then heating at 90 ° C. for 1 hour. Table 1 shows the characteristics of the ring-shaped bonded magnet manufactured in the same manner as in Example 1.

Example 3 Phenol resin 1 manufactured by Dainippon Ink (trade name: Praiophen) was used as the dipping treatment and the curing treatment in Example 1.
Table 1 shows the characteristics of the ring-shaped bonded magnet produced in the same manner as in Example 1 except that the MEK solution containing 0% was immersed for 5 minutes and then heat-treated at 180 ° C. for 2 hours.

Example 4 In Example 1, as the dipping treatment and the hardening treatment, after dipping for 10 minutes in an N-methyl-2-pyrrolidone solution containing 15% of polyaniline (trade name: anilide) manufactured by Nitto Denko, 1
The characteristics of the ring-shaped bonded magnet manufactured in the same manner as in Example 1 except that the heat treatment at 20 ° C. for 1 hour was performed are shown in Table 1.
Shown in.

Example 5 In Example 1, the dipping treatment and the curing treatment were carried out by dipping in an epoxy resin (trade name Epicoat) manufactured by Yuka Shell Co., Ltd. containing a liquid at room temperature for 10 minutes, followed by vacuum impregnation for 1 minute at 150 ° C.
Table 1 shows the characteristics of the ring-shaped bonded magnet manufactured in the same manner as in Example 1 except that the time-hardening treatment was performed.

Example 6 After performing impregnation treatment, curing treatment, and then barrel polishing treatment in the same manner as in Example 5, electroless Ni plating was applied to 3
After performing μm, electric Ni plating was performed. In this case, N
The i-plated layer had an outer diameter of 25 μm and an inner diameter of 20 μm.

The Ni-plated ring-shaped bonded magnets of Examples 1 to 6 above did not show pinholes by the ferroxyl test and rusted even in the weather resistance test at 80 ° C. × 90% temperature × 500 hours. Was not recognized.

[0029]

[Table 1]

Example 7 12.5Nd-11.5Co-6B-1Ga-69Fe
An ingot having a composition of (at%) was obtained by casting in a water-cooled copper mold in which high frequency melting was performed in Ar, and then roughly crushed to 35 mesh or less by a hydrogen storage crushing method. afterwards,
After heating in hydrogen at 800 ° C. for 2 hours, it was vacuum treated to 10 ⁻⁶ Torr while being stored at 800 ° C., and then cooled to room temperature. After sizing this powder to 150 μm or less, 2 wt% of epoxy resin was added and kneaded, and the mixture was mixed in a magnetic field of 10 kOe for 6 minutes.
After molding at a pressure of Ton / cm ^2, the mixture was heat-treated at 150 ° C. for 1 hour to prepare an anisotropic bonded magnet of 8 × 10 × 12 mm. The magnet characteristics are Br8.6kG,
(BH) max17.5MGOe, iHc12.5kO
e, Hk 5.5 kOe, and density 6.3 g / cm ³ . This magnet was impregnated and polished in the same manner as in Example 5, and then Ni-plated. The film thickness of Ni plating is 25 μm, and the porosity before Ni plating is 0.1%.
Met. Also, after Ni plating, 80 ° C × temperature 90% ×
No rust was observed even in the weather resistance test for 500 hours. The magnet characteristics after the weather resistance test were Br8.5 kG,
(BH) max17.3MGOe, iHc12.4kO
e, Hk5.2 kOe, and no deterioration was observed.

[0031]

According to the present invention, the R-Fe-B based bonded magnet is impregnated with an inorganic material such as glass or a resin to impregnate the holes of the magnet with the inorganic material such as glass or a resin, and further subjected to barrel polishing and sand blasting. By performing surface polishing treatment such as treatment, the surface can be modified while maintaining the impregnation effect, and even if it is directly electroplated or electroless plated, harmful plating solution and cleaning solution are prevented from entering. Therefore, there is no deterioration of corrosion resistance such as rusting from the inside and peeling of the plating layer, and the magnet surface is exposed by the polishing process, improving the electrical conductivity and making the surface uniform, and the adhesion of the plating film is improved. Further, since the deburring of the magnet edge portion and R processing can be performed in the polishing process, a uniform plating film can be formed on the entire surface, and the corrosion resistance and heat resistance are further improved. Furthermore, by applying electroless plating to the base, it is possible to perform uniform plating on small holes and complex shapes, and to improve the electrical conductivity before electroplating, the difference in film thickness between the inner and outer diameters in the ring shape is small. Become. In addition, since there is no resin layer, it has the effect of improving heat resistance, and because the plating film strength and hardness are improved, the mechanical fracture strength is greatly improved, and there are various advantages in appearance, handling, transportation, etc. . Barrel plating, general watt bath, etc. can be adopted for the plating treatment, and it can be provided inexpensively with good mass productivity.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C23C 26/00 B C25D 7/00 K H01F 1/053 1/08

Claims (8)

[Claims] 1. An R-Fe-B based bonded magnet having an inorganic material such as glass or a resin impregnated in the pores thereof, or a resin, wherein a plating layer is directly formed on the bare surface of the magnet material itself. -Fe-B based bonded magnet. 2. The R—Fe—B based bonded magnet according to claim 1, wherein the porosity of the magnet is 3% or less. 3. An R-Fe-B based bonded magnet is impregnated with a resin to impregnate pores of the magnet with an inorganic material such as glass or a resin, and a resin layer is formed on the surface of the magnet. A method for producing an R-Fe-B based bonded magnet, which comprises forming a plating layer on the layer. 4. An R-Fe-B based bonded magnet is impregnated with an inorganic substance such as glass or a resin to impregnate pores of the magnet with the inorganic substance such as glass or a resin, and then a glass or the like formed on the surface of the magnet. A method for producing an R-Fe-B based bonded magnet, which comprises removing an inorganic material or a resin layer. 5. An R-Fe-B based bonded magnet is impregnated with an inorganic material such as glass or a resin to impregnate pores of the magnet with the inorganic material such as glass or a resin, and then the glass or the like formed on the surface of the magnet. R-Fe-B characterized by removing an inorganic material or a resin layer and further forming a plating layer on the magnet surface
-Based bonded magnet manufacturing method. 6. The method for producing an R—Fe—B based bonded magnet according to claim 5, wherein the means for forming the plating layer is an electroless plating method. 7. The method for producing an R—Fe—B based bonded magnet according to claim 5, wherein the plating layer forming means is an electrolytic plating method. 8. The method for producing an R—Fe—B based bonded magnet according to claim 5, wherein the plating layer is formed by an electroless plating method, and then the plating layer is further formed by an electrolytic plating method.