CN1279810A - High corrosion-resistant R-Fe-B-base bonded magnet and method of manufacturing the same - Google Patents

Abstract

A method of efficiently manufacturing R-Fe-B-base bonded magnets of various shapes such as ring shape and disk shape having a high corrosion resistance and capable of being plated electrically with ease, wherein the corrosion resistance of the magnet is improved by forming a conductive film of a metal on the surface thereof with tight adhesion, uniformity and efficiency. The method comprises filling the holes of the magnet with polishing powder, inorganic powder and polishing chips, fixing these materials in the holes by fat of a vegetable medium and sealing the resultant holes, and barrel-polishing the magnet by a barrel unit in the dry process with indefinitely shaped, i.e. spherical, massive or acicular (wiry) pieces of a required size of Cu, Sn, Zn, Pb, Cd, In, Au, Ag, Fe, Ni, Co, Cr and Al and such pieces of alloys thereof used as a metallic medium. Said fine pieces of metals such as Cu are press fitted into a resin surface and holes of the bonded magnet and cover the surface and holes and further, cover the surfaces of particles of magnetic powder whereby a very uniform conductive film can be formed on the surface of the bonded magnet, so that it becomes possible to subject the bonded magnet to electric plating excellently and obtain a plated R-Fe-B-base bonded magnet of a high corrosion resistance and with minimum deterioration of the magnetic properties.

Description

R-Fe-B based bonded magnet with high corrosion resistance and its manufacturing process

technical field

The present invention relates to bonded magnets made into various shapes such as rings or disks, the corrosion resistance of which is improved by a clean metal film, the invention relates to highly resistant Corrosive R-Fe-B based bonded magnet and its manufacturing process. In this process, the pores are first filled with polishing powder, bonded magnet polishing shavings and inorganic powders by dry drum polishing technology to seal the pores and finish the surface; or, instead of using this sealing method, use The alloy blocks of Cu, Sn, Zn, Pb, Cd, In, Au, Ag, Fe, Ni, Co, Cr, Al and the above elements are used as the metal medium, and the fine fragments ground from the above metal sheets are pressed by dry drum polishing. or, by coating the surface of the magnet powder with a layer of fine metal fragments, the surface of the magnet is given sufficient conductivity to enable direct plating instead of electroplating. Electroless plating; or, first form the above-mentioned aluminum coating, and then perform zinc replacement treatment to form a high-corrosion-resistant coating that can be mass-produced with high efficiency, and is no longer limited to electroplating nickel or other post-treatment plating technologies.

Background technique

Today, rubber magnets and plastic magnets (made in various shapes such as rings or disks) called bonded magnets are developing towards higher performance, from conventional isotropic bonded magnets to anisotropic Bonded magnets; from ferrite-based bonded magnets to rare-earth-based bonded magnets with higher magnetization, and also from the use of Sm-Co magnetic materials to the use of R-Fe-B magnetic materials, the R-Fe-B Magnetic materials have high magnetic properties in sintered magnets, and the maximum energy product can reach 50MGOe or higher.

However, R-Fe-B magnets have the problem that because their magnet alloy composition contains a large amount of iron and an extremely oxidizable constituent phase, they are prone to rust, so they need to be coated with electrolytic deposition, spraying, dipping or soaking. Resin layers of various components are formed on the surface (see Japanese Patent Application Publication No. H1-166519/1989, Japanese Patent Application Publication No. H1-245504/1989).

For the resin coating method currently used to improve the corrosion resistance of R-Fe-B bonded magnets, for example, in terms of the spraying method used for ring-shaped bonded magnets, the loss of coating materials is large; due to the need to reverse both sides, Therefore, many process steps are involved; and this method also has the problem of poor uniformity of film thickness.

In addition, for the electroplating method, although the thickness of the film layer is uniform, each magnet needs to be connected to the electrode; and the imprint left by the electrode must be removed after the plating is completed, so it needs to be trimmed. Therefore, this method requires a large number of process steps and is especially suitable for small magnets.

When using the dipping method, it is difficult to achieve a specific uniform thickness of the coating due to dripping of the coating material and other problems. Also, with porous bonded magnets, the pores thereof cannot be filled sufficiently, which causes problems such as swelling during drying, and causes product blocking.

For the mass production method of forming a metal coating, a solution is to carry out metal plating on the sintered R-Fe-B magnet (see Japanese Patent Application Publication No. S60-54406/1985 and Japanese Patent Application Publication No. S62-120003 /1987), but the surface of the R-Fe-B bonded magnet is porous, and the conductivity of the exposed resin part is poor. Therefore, the electroplating solution will remain on the surface of the bonded magnet after electroplating, and the resin part cannot be fully formed. plating, thereby causing pinholes (unplated portions); and causing rust.

Therefore, there are methods of selecting plating solutions which are harmless even if they permeate into polytropic bonded magnets and remain there (Japanese Patent Application Laid-Open No. H4-276092/1992). There have also been methods in which a resin coating is first formed on an undercoat layer, followed by plating (Japanese Patent Application Publication No. H3-11714/1991, Japanese Patent Application Publication No. H4-276095/1992).

However, it is difficult to adjust the pH of the plating solution or to make them completely harmless, and any solution with high film-forming ability has not been found, and the fluctuation of the thickness of the undercoat layer is an unstable factor of the plating layer, but forming a sufficient thickness A low base coat will make surface plating unnecessary.

It has been proposed to use a plating solution of a specific composition to perform nickel plating with high film-forming efficiency on R-Fe-B bonded magnets (Japanese Patent Application Publication No. H4-99192/1992). But this method still has the danger that the plating solution will penetrate into the bonded magnet and remain there, causing rust.

On the other hand, for structural materials, copper strike plating, which is usually used before nickel plating, is either strongly alkaline or strongly acidic, so it is not suitable for processing R-Fe-B bonded magnets.

In addition, in order to make electronic components wear-resistant, and as a corrosion-resistant treatment technology for automotive dashboards and similar parts, practical NiP plating belongs to high-temperature acidic solutions, but this method is not suitable for R-Fe- B Bond the magnet because it causes corrosion inside the magnet.

Therefore, in order to provide an R-Fe-B bonded magnet and a manufacturing method thereof, the plating solution, cleaning solution, etc. cannot penetrate and remain in the porous R-Fe-B bonded magnet, and can efficiently form a nickel plating layer or other Plating, and significantly increasing its resistance, provides the following methods.

(1) A method of plating the surface of an R-Fe-B based bonded magnet with a mixture of resin and conductive powder to form a conductive film layer on the surface of the base material.

(2) A method of forming an adhesive resin layer on the surface of an R-Fe-B-based bonded magnet, bonding magnetic powder thereon, and forming a conductive film layer on the surface of the base material (Japanese Patent Application Publication No. H5 -302176/1993).

(3) A method of forming a conductive film layer on the surface of an R-Fe-B based bonded magnet with resin and conductive powder, followed by surface finishing treatment (Japanese Patent Application Laid-Open No. H9-186016/1997).

However, in the above-mentioned three methods, various resins are used for sealing the pores of the base material, thus inevitably complicating the process, including undesirable resin coating (soaking) and hardening (finishing) ).

In addition, in the method of coating (soaking) a base material with a resin, it is difficult to uniformly coat the resin on the surface of the base material, and it is also difficult to obtain a coated product with excellent dimensional accuracy even if barrel polishing is subsequently used; and, When using a conductive coating, the resin layer contains conductive substances or metal powders. Therefore, even if the surface of the bonded magnet is coated with a resin part, it will be better than the base material of the R-Fe-B-based bonded magnet. There will still be considerable exposed areas and low-conductivity parts on the resin-coated surface, making it difficult to obtain a surface with good uniform conductivity and prone to pinholes during the plating process.

Therefore, the present inventor proposes a kind of method: adopt the mixture of polishing agent and plant-derived material or the plant-derived material that the surface has been modified by inorganic powder to do polishing medium, carry out drum polishing technique with dry method, the polishing agent Powder and bonded magnet polishing shavings stick to the pores of the bonded magnet with oily components in plant-derived materials while sealing the pores and finishing its surface, and form a conductive layer by electroless copper plating with an alkaline plating solution.

However, this method still has some problems. Due to the use of electroless copper plating, the service life of the plating solution is short; and in order to obtain a good plating layer, the control of the plating solution is difficult. In addition, although the corrosion resistance and dimensional accuracy of this method are superior to existing processes, higher corrosion resistance is required for various applications today.

Contents of the invention

One of the objects of the present invention is to provide an R-Fe-B bonded magnet, which has extremely high corrosion resistance and does not rust even when subjected to high-temperature and high-temperature tests for a long time. Another object is to provide a production method by which various corrosion-resistant film layers can be uniformly formed on R-Fe-B bonded magnets, and in order to obtain high corrosion resistance, the adhesion strength is also high. extremely high.

Another object of the present invention is to provide a kind of manufacture method of high corrosion resistance R-Fe-B bonded magnet, this method comprises the best method of forming the corrosion-resistant film layer of high adhesive strength and high dimensional accuracy on the magnet surface. Industrial production steps, and the problem of preventing plating solution, cleaning solution, etc. from penetrating into and remaining in the porous R-Fe-B bonded magnet that occurs in the conventional electroless plating method.

The present inventors believe that in the electroplating method for making R-Fe-B bonded magnets have excellent corrosion resistance and surface cleanliness, it is very important to give the surface of the base material an extremely uniform conductivity. For this reason, it is essential to obtain the above-mentioned conductive film Layer methods have been studied in various ways. It was found that the R-Fe-B-based bonded magnets were dry-processed with a roller device, and the required size and shape were indeterminate or spherical, or block or needle-shaped (linear) copper sheets were used as the metal medium. The ground fine fragments will be pressed into the porous part of the bonded magnet and the surface of the resin to form a film layer, and the copper fragments will also be coated on the surface of the magnetic powder, so a layer can be formed on the surface of the R-Fe-B bonded magnet An extremely uniform conductive film layer, so good electroplating can be performed, so that an electroplated R-Fe-B based bonded magnet product with excellent corrosion resistance and almost no deterioration in magnetic properties can be obtained.

The inventors of the present invention have also conducted various studies to solve the above-mentioned problem of the surface finish of the bonded magnet. It was found that: through dry barrel polishing of porous R-Fe-B bonded magnets, polishing agents made of inorganic powders such as sintered Al ₂ O ₃ , SiC and vegetable sources such as fruit peels and corn cobs A mixture of materials is used as a polishing medium, or a mixture of the above-mentioned polishing agent and the plant-derived material whose surface has been modified by the above-mentioned inorganic powder is used as a polishing medium, and the oily component in the plant-derived material can be used to form a bond. The surface oxide layer polishing dust of the magnetic powder of the magnet, the inorganic powder for modification, and the polishing agent powder adhere to the porous part of the magnet, thereby sealing its pores while finishing its surface. Therefore, after dry barrel polishing, a conductive film layer can be directly formed on the surface of the magnet base material, thereby obtaining an R-Fe-B based bonded magnet with good surface finish and better corrosion resistance.

The present inventors have further realized that in addition to the above-mentioned copper sheets, other materials can also be used as metal media in dry barrel polishing, namely Sn, Zn, Pb, Cd, In, Au and Ag, and soft metal flakes of Fe, Ni, Co, and Cr.

The present inventors have further found that by performing dry barrel polishing in a roller apparatus, using aluminum flakes of indeterminate shape as the metal medium, fine fragments of aluminum grinding are pressed into the porous part of the surface of the bonded magnet and the surface of the resin to form a film layer, or on the surface of the R-Fe-B bonded magnet, the surface of the aluminum film layer formed by similarly coated aluminum fine fragments on the surface of the magnetic powder is subjected to zinc replacement treatment, which can prevent aluminum influence during the electroplating process ), to ensure good electroplating, thereby obtaining an electroplated R-Fe-B-based bonded magnet product with excellent corrosion resistance and almost no deterioration in magnetic properties. The present invention has been completed as above. BEST MODE FOR CARRYING OUT THE INVENTION

According to the present invention, the high corrosion resistance R-Fe-B base bonded magnet is characterized in that there is a layer of Cu, Sn, Zn, Pb, Cd, In, Au, Ag, Fe, Ni, Co, Cr and A metal coating formed of a metal sheet of Al or its alloy, which is press-fitted and coated on the porous part and resin surface constituting the surface of the R-Fe-B-based bonded magnet, or the coating is formed by coating on the composition The fine metal fragments on the surface of the magnetic powder on the surface are formed, and an electroplating layer is formed on the intermediate metal coating.

According to the present invention, the high corrosion resistance R-Fe-B base bonded magnet is also characterized in that its surface has a layer of porous parts that are pressed in by the above-mentioned metal fragments and coated on the surface of the R-Fe-B base bonded magnet. and the metal coating layer formed on the surface of the resin, or, the porous part constituting the surface of the R-Fe-B-based bonded magnet has been covered with a plant-derived material containing polishing agent powder, bonded magnet polishing shavings, and inorganic powder After filling with the oily component in the medium, the coating is formed of fine metal fragments coated on the surface of the magnetic powder constituting the surface, and an electroplating layer is formed on this intermediate metal coating.

According to the present invention, another feature of the high corrosion resistance R-Fe-B base bonded magnet is that it has a layer of aluminum coating layer, which is pressed in by fine aluminum fragments and coated on the structure. The surface of the magnet is formed from the porous part of the surface and the surface of the resin or is formed from fine aluminum fragments coated on the surface of the magnetic powder constituting the surface, the surface of the magnet has a layer of zinc formed by zinc replacement treatment, also in the An electroplating layer is formed on the middle metal layer.

The R-Fe-B based bonded magnets considered in the present invention refer to isotropic bonded magnets and anisotropic bonded magnets, which can be produced by various methods. For example, in the molding method, the thermosetting resin, coupling agent and lubricant are first added and kneaded in the magnetic powder with the required components and properties, and then molded, heated, and resin cured; in injection molding, extrusion molding In the method or rolling molding, the thermosetting resin, coupling agent and lubricant are first added and kneaded in the magnetic powder, and then injection molding, extrusion molding or rolling molding are performed.

For R-Fe-B magnetic powder, whether it is isotropic powder or anisotropic powder, it can be used, and they are made by any of the following methods, including: melting and pulverizing method (required R-Fe-B Alloy melting, casting, followed by grinding), direct reduction diffusion method (directly obtain powder by Ca reduction), alloy rapid cooling method (required R-Fe-B alloy melting, fabrication of foil strips by jet casting, followed by foil with pulverization and annealing), aerosol method (required R-Fe-B alloy is melted, powdered by aerosol method and heat treated), mechanical alloying method (the required metal raw material is made into powder, and then mechanically alloyed Chemical method to make fine powder and heat treatment, or HDDR method (required R-Fe-B alloy is heated in hydrogen to make it pulverized and recrystallized).

In the present invention, the total amount of rare earth element R in the R-Fe-B bonded magnet is 10at% to 30at% of the composition, but preferably contains at least one of Nd, Pr, Dy, Ho and Tb elements, or at least Contains one of La, Ce, Sm, Gd, Er, Eu, Tm, Yb, Lu and Y elements. Usually one rare earth element can meet the requirements, but in practice, since mixtures of two or more rare earth elements are easy to obtain (such as mixed rare earth alloys or mixtures of praseodymium and neodymium), these mixtures can also be used, where R does not have to be A pure rare earth element, in addition, may be conveniently used in consideration of industrial feasibility, for example, containing impurities unavoidable in the manufacturing process.

Rare earth R is an indispensable element in the above magnet powder. If the rare earth content is less than 10at%, the crystal structure of the magnet will become the same cubic crystal as α-Fe, so high magnetic properties, especially high coercive force cannot be obtained; on the other hand, if the rare earth content exceeds 30at% , many R-rich non-magnetic phases will be formed, so that the residual magnetic flux density (Br) is reduced, and a magnet with excellent performance cannot be obtained. Therefore, the content of rare earth should be 10at% ~ 30at%.

B is also an essential element in the above magnet powder. If the B content is less than 2at%, the rhombic structure in the magnet will become the main phase, so that high coercive force (iHc) cannot be obtained; on the other hand, if the B content is higher than 28at%, many B-rich non- The magnetic phase reduces the residual magnetic flux density (Br), making it impossible to obtain an excellent magnet. Therefore, the B content should be 2at% to 28at%.

Fe is also an essential element in the above magnets. If the Fe content is less than 65 at%, the residual magnetic flux density (Br) will decrease; and if the Fe content exceeds 80 at%, high coercive force cannot be obtained. Therefore, the Fe content should be 65 at% to 80 at%.

Substituting part of Fe with Co can improve the temperature characteristics of the magnet without impairing its magnetic properties. However, if the amount of Co substituting Fe exceeds 20%, the magnetic properties will decrease instead, which is undesirable. When the substitution amount of Co is 5 at% to 15 at% of the total amount of Fe and Co, Br will increase compared with no substitution, so this is suitable for obtaining high magnetic flux density.

In addition, in addition to R, B and Fe, impurities that inevitably exist in industrial production are allowed, for example, at least one element in the following group substituting part B can improve the manufacturability of the magnet and reduce its cost, the group The elements are: C (4.0wt% or less), P (2.0wt% or less), S (2.0wt% or less) and Cu (2.0wt% or less), but the total The amount is 2.0 wt% or less.

At least one element of Al, Ti, V, Cr, Mn, Bi, Nb, Ta, Mo, W, Sb, Ge, Ga, Sn, Zr, Ni, Si, Zn and Hf can also be added to the magnetic powder , can increase the coercive force, increase the squareness ratio of the hysteresis loop, improve its manufacturability or reduce its cost. The upper limit of the addition of the above elements should be within the following range: this range can meet the bonded magnet (BH) _max and (Br) the various conditions required for the expected value.

In addition, in the present invention, the binder used in the injection molding method can be resins such as 6PA, 12PA, PPS, PBT or EVA. Among them, the binder can be PVC, NBR, CPE, NR or Hyperon, etc., and the binder that can be used in molding is epoxy resin, DAP or phenolic resin, etc., if necessary, known metal binders can be used , Other auxiliary additives, such as lubricants to assist molding, binders for resins and inorganic fillers, and silane-based or titanium-based coupling agents can also be used.

In the present invention, during the sealing and finishing treatment, the medium used for barrel polishing is a mixture of polishing agent and plant-derived material, and the polishing agent is, for example, ceramic materials or metals such as sintered inorganic powders such as Al ₂ O ₃ , SiC, etc. Balls, the plant-derived material is, for example, plant shells, wood chips, fruit peels, or corn cobs, the polishing medium or the above-mentioned polishing agent and the above-mentioned plant whose surface has been modified by the above-mentioned inorganic powder such as Al ₂ O ₃ , SiC, etc. A mixture of source materials, using the above mixture as a polishing medium for barrel polishing, can be used for finishing and sealing of bonded magnets.

For the dry drum polishing for realizing sealing and finishing treatment and forming a metal layer on the bonded magnet surface in the present invention, known drums can be used, such as the rotary drum of 20 to 50 rpm as the commonly used rotating speed, and the rotating speed is 70 to 200 rpm Centrifugal rollers, or vibrating rollers with an amplitude greater than or equal to 0.5mm but not exceeding 50mm.

In addition, the atmosphere during barrel polishing is usually air, but in order to prevent the magnet from being oxidized due to frictional heat during the barrel polishing process (this depends on the type of medium), an inert atmosphere such as N ₂ , Ar, and He gas can be used. Use alone or in combination.

In the present invention, when a rotary drum or a vibrating drum is used for sealing and finishing treatment, if the total amount of bonded magnets, polishing agents, and plant-derived materials loaded into the drum is less than 20%, the amount of treatment is too small. It is suitable for practical use; if it exceeds 90%, there will be insufficient stirring and insufficient polishing, so the amount added should be 20% to 90% of the internal volume.

Among the present invention, there is no specific limitation to the polishing medium used during sealing and finishing treatment, yet, the particle size of the polishing agent in the polishing medium mixture should be 1～7mm, preferably about 3～5mm, and the length of the material of plant origin It should be 0.5-3mm, preferably about 1-2mm, or the polishing medium is a mixture of the above-mentioned polishing agent and the above-mentioned plant-derived material whose surface has been modified by inorganic powder, and the mixture of the magnet and the polishing medium should be stirred evenly , to ensure relative movement between them.

For the above-mentioned plant-derived material whose surface has been modified by inorganic powder, the oily component of the plant-derived material used, such as wax, is kneaded to uniformly cover the surface with a layer of particles with a particle size of 0.01 to 3 μm. Al ₂ O ₃ , SiC, ZrO or MgO inorganic powder. The particle size of the polishing agent powder used as the sealing layer, the inorganic powder used to modify the surface of the plant-sourced material, and the polishing shavings of the bonded magnet should be 0.01-3 μm.

In the polishing medium, the ratio of plant-derived material to polishing agent (plant-derived material/abrasive) must be between 1/5 and 2, and the preferred ratio is 1. The mixing ratio of bonded magnet and polishing agent (bonded magnet/ Medium) can be 3 or lower.

In the present invention, the role of the above-mentioned polishing agent is to effectively grind away the surface oxide layer of the magnet, finish its surface and impact and harden the polishing by polishing agent powder, inorganic powder for modifying the surface of the material of plant origin, and bonded magnet. The role of the above-mentioned plant-derived material is to enhance the bonding strength of the sealing material by effectively releasing its oily components.

In the present invention, after surface finishing treatment, the porosity of the bonded magnet can be reduced to 3% or lower, and it is also possible to not only finish and seal the surface of the bonded magnet, but also remove the surface oxide layer of the magnet, thereby The active R-Fe-B magnet powder surface is obtained.

In the present invention, any known roller device can be used, whether it is rotary, vibratory or centrifugal, etc., and metal sheets are used for dry roller polishing, and metal sheets of indeterminate shapes can be used, no matter spherical, block or needle ( linear), etc. As for the size of the metal sheet, if it is less than 0.1mm, it will take too much time to fully press in and form a coating layer, so it is impractical; and if the size exceeds 10mm, the irregularity of the surface will increase, and the use of This metal sheet cannot cover the entire surface of the magnet, so the size of the metal sheet should be 0.1-10mm, preferably 0.3-5mm, most preferably 0.5-3mm.

In addition, in the present invention, the metal flakes loaded into the dry drum do not have to be the same shape or size, but can be a mixture of various shapes and sizes, and it is also allowed to mix fine metal powder with metal flakes of irregular shapes. In addition, these metal sheets can be only the metal mentioned above or an alloy or a copper composite metal whose copper core is covered by different metals such as iron, nickel or aluminum.

It is also necessary to make the loading ratio in dry barrel polishing, that is, the volume ratio of the magnet to the metal sheet (magnet/metal), be 3 or lower. When this ratio exceeds 3, in order to make the metal fine fragments press into the magnet and form a coating The required time is too long, which is not suitable for practical use, and the magnetic powder particles will also loosen on the surface of the bonded magnet.

The amount of bonded magnets and metal sheets loaded into the drum polishing machine is preferably 20% to 90% of the internal volume of the polishing machine. If it is less than 20%, the amount of processing is too small and is not suitable for actual use; and if it exceeds 90%, stirring will occur. Insufficient to achieve adequate polishing.

The fine metal fragments that are pressed in and form the coating layer are powdery or needle-like. When the length exceeds 5 μm, the adhesion between the fragments and the surface of the magnet is poor, which will cause problems such as bonding defects and peeling during the electroplating process. Therefore, its length should not exceed 5 μm, preferably not exceed 2 μm.

In the present invention, as for the pressing of fine metal fragments and forming a coating layer, the fine metal fragments are pressed into and coated on the surface of the soft resin and the porous part on the surface of the bonded magnet, and coated on the magnetic layer on the surface of the bonded magnet. On the surface of the powder, near the surface, the number of fine metal fragments pressed into the resin surface and the porous part is large, while the number of pressed into the inside of the resin layer gradually decreases.

In the present invention, the thickness of the indentation layer of metal fragments on the resin surface and the porous portion should be 0.1 µm or more, but not more than 2 µm. If it is less than 0.1 µm, sufficient conductivity cannot be obtained, and if it exceeds 2 µm, although there is no problem in performance, it takes a long time and is not suitable for actual operation.

The thickness of the metal coating layer on the surface of the magnetic powder on the surface of the bonded magnet should be 0.2 μm or less, because the reaction between the surface of the magnetic powder and the fine metal fragments is a mechanochemical action, if the thickness exceeds 0.2 μm, will reduce the adhesive performance.

In the present invention, the rotational speed of the dry drum polishing should be 20-50 rpm for the rotating drum, 70-200 rpm for the centrifugal drum, and 50-100 Hz for the vibrating drum polishing with an amplitude of 0.3-10 mm.

In the present invention, when the press-in coating layer of fine metal fragments is formed on the surface of the magnet using the barrel polishing method, the atmosphere of the barrel polishing may be air. However, considering that the friction and heat generation between the ground fine metal fragments, the magnetic powder on the surface of the magnet, and the indeterminate metal sheet used as the medium will cause oxidation, the conductivity will decrease, and uniform plating cannot be performed, resulting in resistance to corrosion. erosive decline. Therefore, the preferred atmosphere in the barrel polishing method is an inert gas or inert gas and mixtures of such gases, such as _N2 , Ar or He.

In the present invention, the surface aluminum cladding is subjected to zinc replacement treatment to prevent aluminum overflow in the subsequent electroplating process. The solution used in the zinc replacement treatment contains zinc oxide, sodium hydroxide, ferric chloride or Rossel's salt and the like. Immerse in the bath liquid during processing, the temperature of the bath liquid is 10-25°C, and the processing time is 10-120 seconds.

In the zinc replacement process, the process sequence should be cleaning→zinc replacement→cleaning. If contaminants or other adhering materials are present on the aluminum cladding surface, the cleaning process should be degreased by immersion in a solution of sodium carbonate and sodium triphosphate. When forming the zinc replacement layer, the outermost layer should be in the form of ZnO _x (x=0-1), and the thickness of the zinc layer should be 0.1 μm or less. If the thickness of this layer of zinc exceeds 0.1 μm, it will cause bonding defects, so this should be avoided.

In the present invention, the electroplating method should contain at least one metal selected from Ni, Cu, Sn, Co, Zn, Cr, Ag, Au, Pb and Pt or its alloy containing B, S or P, and electroplating nickel can especially To meet the requirements, the thickness of the electroplating layer should be 50 μm or less, preferably 10-30 μm. In the present invention, the commonly used watt tank can be used for electroplating to effectively utilize the above-mentioned fine metal fragments formed in the resin surface and porous parts to press into the coating layer, thereby obtaining excellent bonding performance and corrosion resistance.

Specifically, in the electroplating method using nickel plating solution, the sequence of process steps should be cleaning→electroplating nickel→cleaning→drying, and the pH value of nickel plating solution should be adjusted to 4.0-4.6 with alkaline nickel carbonate. , and the treatment temperature should be 50-60°C.

In electroplating nickel, the above-mentioned electroplating solution should be used to introduce a specified current, and the electrolytic nickel plate should be used as the anode. During nickel electroplating, the nickel on the nickel anode plate should be deposited stably. The sulfur-containing Estland nickel sheet can be used in the electrode. In the electroplating method using nickel electroplating solution, the process sequence should be cleaning→electroplating→cleaning→drying, wherein the drying is preferably carried out at a temperature of 70°C or higher.

Various plating baths can be used depending on the shape of the bonded magnet, for ring bonded magnets rack plating or drum plating is preferred.

Example

Example 1

The average particle size of the alloy powder used is 150 μm, the composition is 12at% Nd, 77at% Fe, 6at% B and 5at% Co, made by ultra-high cooling rate method, adding 2wt% epoxy resin, kneading together, and Formed by pressing under a pressure of 7 tons/ ^cm2 , and then cured at 170°C for 1 hour to produce a ring-shaped bonded magnet with an outer diameter of 22mm, an inner diameter of 20mm, and a height of 3mm. The properties of the bonded magnet obtained in this way are as follows: Br=6.7kG, iHc=8.9kOe, (BH) _max =9.0MGOe.

Using a short rod-shaped copper rod with a diameter of 1 mm and a length of 1 mm, the above-mentioned bonded magnet is placed in a vibrating drum for dry barrel polishing to form a conductive layer composed of fine copper fragments on the surface of the bonded magnet. On the resin surface The thickness of the pressed-in coating layer of copper fragments is about 0.7 μm, and the thickness of the film layer on the surface of the magnetic powder is 0.1 μm.

The conditions of barrel polishing treatment are as follows: the atmosphere is argon, 50 bonded magnets (loose volume 0.15 liters, weight 100 g) and copper fragments of the above size (loose volume 2 liters, weight 10 kg) are loaded, The vibrating drum has a volume of 3.5 liters, a vibration frequency of 70 Hz, and an amplitude of 3 mm. The total volume loaded is 60% of the internal volume of the drum, and the treatment time is 3 hours.

Then, it is cleaned, and nickel is electroplated with a hanger-type electroplating device. After electroplating, the coating thickness is 20 μm at the inner diameter and 22 μm at the outer diameter. The annular bonded magnet thus treated was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 500 hours. After the moisture resistance test, the performance of the magnet is shown in Table 1, and the surface state and film thickness dimensional accuracy during the moisture resistance test are shown in Table 2.

The nickel electroplating conditions are as follows: current density 2A/dm ² , electroplating time 60 minutes, pH value of electroplating solution 4.2, temperature 55°C. The composition of the electroplating solution is: 240g/l nickel sulfate, 45g/l nickel chloride, titrated nickel carbonate (used to adjust the pH value) and 30g/l boric acid.

Comparative example 1

Clean the ring-shaped bonded magnet that obtains with the same method as embodiment 1, carry out electroless copper plating to it afterwards, coating thickness 5 μm, electroplating nickel under the same condition as embodiment 1 then, the ring-shaped bonded magnet after processing like this Carry out the environmental test, the temperature is 80°C, the relative humidity is 90%, and the test time is 500 hours. The results are shown in Tables 1-3.

The electroless copper plating conditions are as follows: the plating time is 20 minutes, the pH value of the plating solution is 11.5, and the temperature of the plating solution is 20°C. The composition of the plating solution is: 29g/l copper sulfate, 25g/l sodium carbonate, 140g/l tartrate, 40g/l sodium hydroxide and 150ml formaldehyde with a concentration of 37%. Comparative example 2

Clean the ring-shaped bonded magnet that obtains with the same method as embodiment 1, form the conductive film of 10 μ m thick with the phenolic resin that is mixed with nickel powder afterwards, electroplating nickel under the same condition as embodiment 1 then, the after such processing The annular bonded magnet was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 500 hours. The results are shown in Tables 1-3.

The formation conditions of the conductive film layer are as follows: the treatment time is 30 minutes, and the treatment solution components are: 5wt% phenolic resin, 5wt% nickel powder (particle size 0.7 μm or lower) and 90wt% MEK (butanone). Comparative example 3

Clean the annular bonded magnet obtained by the same method as in Example 1, then preform a layer of adhesive layer on the magnet with phenolic resin by dipping method, and then adhere silver powder (particle size 0.7 μm or lower) on its surface , form a 7 μm thick conductive film layer with a vibrating roller afterwards, electroplate nickel under the same conditions as Example 1 after the vibrating roller is processed, and the annular bonded magnet after such processing is carried out environmental test (moisture resistance test), temperature 80 ℃, relative humidity 90%, test time 500 hours. The results are shown in Tables 1-3.

The conditions of the vibrating drum treatment are as follows: the volume of the vibrating drum is 3.5 liters, 50 bonded magnets are loaded, the treatment time is 3 hours, and steel balls with a diameter of 2.5 mm and a loose volume of 2 liters are used as the medium.

From Table 1 and Table 2, it can be clearly seen that spot corrosion all occurs in Comparative Example 1 after 100 hours, Comparative Example 2 after 300 hours, and Comparative Example 3 after about 350 hours; on the contrary, for Example 1, even after After 500 hours, there is no spot rust under a 30X microscope. Table 1 Before moisture resistance test After moisture resistance test Magnetic property reduction ratio (%) Br(kG) iHc(kOe) (BH) _max (MGOe) Br(kG) iHc(kOe) (BH) _max (MGOe) Br(kG) ikB (BH) _max (MGOe) Example 1 6.6 8.9 9.0 6.5 8.7 8.8 3.0 2.2 2.2 Comparative example 1 6.4 8.7 8.8 5.7 7.7 7.6 14.9 15.6 15.5 Comparative example 2 6.4 8.9 9.0 6.3 8.5 8.5 6.3 4.4 5.5 Comparative example 3 6.4 8.9 9.0 6.3 8.5 8.5 6.3 4.4 5.5 Magnetic property reduction ratio (%)=[{(initial magnetic property)-(magnetic property after moisture resistance test)}/(initial magnetic property)]×100 Table 2 Surface state after a certain moisture resistance test time Dimensional accuracy of film thickness (μm) Manufacturing method Example 1 No change (no rust) 20±1 Cu film + Ni plating Comparative example 1 Pitting corrosion occurs after 100h 25±2 Electroless Cu plating + Ni plating Comparative example 2 After 300h, micro-pitting corrosion appeared 30±10 Resin conductive layer + Ni plating Comparative example 3 After 350h, micro-pitting corrosion appeared 27±10 Conductive coating + Ni plating Example 2

The average particle size of the alloy powder used is 150 μm, the composition is 12at% Nd, 77at% Fe, 6at% B and 5at% Co, made by ultra-high cooling rate method, adding 2wt% epoxy resin, kneading together, and Formed by pressing under a pressure of 7 tons/ ^cm2 , and then cured at 170°C for 1 hour to produce a ring-shaped bonded magnet with an outer diameter of 26mm, an inner diameter of 24mm, and a height of 5mm. The properties of the bonded magnet obtained in this way are as follows: Br=6.8kG, iHc=9.1kOe, (BH) _max =9.2MGOe.

Put 100 such magnets (200 g) together with _{Al2O3 -} based spherical drum abrasives with an average diameter of 3 mm in a vibrating drum with a volume of 20 liters, and fill 50% of the drum volume with plant-derived materials, plant-derived The material is a walnut kernel with a diameter of about 1 mm whose surface has been modified by Al ₂ O ₃ powder with a particle size of about 1 μm, and then undergoes 120 minutes of dry surface polishing with an amplitude of 20 mm to seal the magnet gap and finish the treatment .

Next, put the bonded magnet into a vibrating drum for dry drum polishing. The vibration frequency is 70 Hz, the amplitude is 3 mm, and the atmosphere is argon. A short rod-shaped copper rod with a diameter of 1 mm and a length of 1 mm is used to form a The conductive layer is composed of fine copper fragments, the depth of the fine copper fragments pressed into the resin surface and the porous part is about 0.7 μm, and the film thickness on the surface of the magnetic powder is 0.1 μm. The conditions of the barrel polishing treatment are as follows: 50 bonded magnets (loose volume 0.15 liters, weight 100 g) and copper fragments of the above size (loose volume 2 liters, weight 10 kg) are loaded, and the volume of the vibrating drum is 3 5 liters, the treatment time is 3 hours, the amplitude is 20mm, and the total volume is 60% of the internal volume of the drum.

Then it was cleaned, and nickel was electroplated with a hanger-type electroplating device. After electroplating, the thickness of the coating film at the inner diameter was 21 μm, and that at the outer diameter was 23 μm. The annular bonded magnet thus treated was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 800 hours. After the moisture resistance test, the performance of the magnet is shown in Table 3, and the surface state and film thickness dimensional accuracy after a certain moisture resistance test time are shown in Table 4.

The nickel electroplating conditions are as follows: current density 2A/dm ² , electroplating time 60 minutes, pH value of electroplating solution 4.2, temperature 55°C. The composition of the electroplating solution is: 240g/l nickel sulfate, 45g/l nickel chloride, titrated nickel carbonate (used to adjust the pH value) and 30g/l boric acid. Comparative example 4

The annular bonded magnet obtained by the same method as in Example 2 was cleaned, then sealed and surface finished in the same manner as in Example 2, cleaned again, and then electroless copper-plated with a thickness of 5 μm. Electroless nickel plating under the same conditions as in Example 2 after the electroless copper plating, the ring-shaped bonded magnet after such processing is carried out the environmental test (moisture resistance test) under the same conditions as in Example 2, and the test results and film thickness are measured Dimensional accuracy (moisture resistance test), the results are shown in Table 3 and Table 4.

The electroless copper plating conditions are as follows: the plating time is 20 minutes, the state value of the plating solution is 11.5, and the temperature is 20°C. The composition of the plating solution is: 29g/l copper sulfate, 25g/l sodium carbonate, 140g/l tartrate, 40g/l sodium hydroxide and 150ml formaldehyde with a concentration of 37%. Comparative example 5

Clean the annular bonded magnet obtained by the same method as in Example 2, then use a mixture of phenolic resin and nickel powder to form a 10 μm thick conductive resin film on the surface of the magnet under the following conditions, and then place it in a vibrating drum. 60% volume magnets and 5mm copper balls were barrel polished for 60 minutes at an amplitude of 20mm to finish and polish.

Then under the same conditions as in Example 2, electroplate nickel, the annular bonded magnet after such processing is carried out environmental test (moisture resistance test) under the same conditions as in Example 2, measure test result and film layer thickness dimensional accuracy (moisture resistance test), the results are shown in Table 3 and Table 4.

The formation conditions of the conductive coating layer are as follows: the treatment time is 30 minutes, and the treatment solution components are: 5wt% phenolic resin, 5wt% nickel powder (particle size 0.7 μm or lower) and 90wt% MEK (butanone).

As can be seen from Table 4: after 700 hours, comparative example 4 and comparative example 5 all appear spot corrosion after 600 hours: and on the other hand, for embodiment 2, even through 800 hours, there is no rust under a 30 times microscope Spotted rust. table 3 Before moisture resistance test After moisture resistance test Magnetic property reduction ratio (%) Br(kG) iHc(kOe) (BH) _max (MG0e) Br(kG) iHc(kOe) (BH) _max (MGOe) Br(kG) iHc(kOe) (BH) _max (MGOe) Example 2 6.7 9.0 9.1 6.5 8.7 8.7 4.4 4.4 5.4 Comparative example 4 6.7 8.9 9.1 6.3 8.5 8.3 7.4 6.6 9.8 Comparative example 5 6.7 9.0 9.1 6.3 8.7 8.2 7.4 7.7 10.9 Magnetic property reduction ratio (%)=[{f (initial magnetic property)-(magnetic property after moisture resistance test)}/(initial magnetic property)]×100 Table 4 Surface state after a certain moisture resistance test time Dimensional accuracy of film thickness (μm) Manufacturing method Example 2 No change (no rust) 22±1 Sealing treatment+Cu film layer+Ni plating layer Comparative example 4 Pitting corrosion occurs after 700h 25±2 Sealing treatment + electroless Cu + Ni plating Comparative example 5 Pitting corrosion occurs after 600h 28±5 Resin conductive layer + finishing Ni plating Example 3

The ring-shaped bonded magnet of 25mm (outer diameter) × 23mm (inner diameter) × 3mm (height) was manufactured by the same method as in Example 1, and its properties are as follows: Br=6.9kG, iHc=9.1kOe, (BH) _max =9.3MGOe.

Put the above-mentioned bonded magnet into a vibrating roller for dry roller polishing, use a short rod-shaped tin rod with a diameter of 2mm and a length of 1mm to form a conductive layer composed of fine tin fragments on the surface of the bonded magnet, and the tin fragments on the resin surface The indentation thickness is about 0.9 μm, and the coating thickness on the surface of the magnetic powder is 0.4 μm. The conditions during barrel polishing treatment are the same as those in Example 1.

Then it is cleaned, and copper is electroplated with a hanger-type electroplating device, and then nickel is electroplated. After electroplating, the coating thickness is 22 μm at the inner diameter and 23 μm at the outer diameter. The annular bonded magnet thus treated was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 500 hours. After the moisture resistance test, the performance of the magnet is shown in Table 5, and the surface state and film thickness dimensional accuracy after a certain moisture resistance test time are shown in Table 6.

The copper electroplating conditions are as follows: current density 2.5A/dm ² , electroplating time 5 hours, pH value of electroplating solution 10, temperature 40°C. The composition of the electroplating solution is: 20g/l copper, 10g/l free cyanide. Nickel electroplating condition is the same as embodiment 1.

Example 4

The ring-shaped bonded magnet made by the same method as in Example 3 is put into a vibrating drum for dry drum polishing, and a short rod-shaped zinc rod with a diameter of 1 mm and a length of 2 mm is used to form a fine zinc oxide layer on the surface of the bonded magnet. For the conductive layer composed of fragments, the indentation thickness of the zinc fragments on the resin surface is about 0.8 μm, and the coating thickness on the surface of the magnetic powder is 0.2 μm. The conditions during barrel polishing were the same as in Example 1.

Then copper and nickel were electroplated under the same conditions as in Example 3, and the annular bonded magnet thus treated was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 500 hours. After the moisture resistance test, the performance of the magnet is shown in Table 5, and the surface state and film thickness dimensional accuracy after the moisture resistance test are shown in Table 6.

Example 5

Put the annular bonded magnet made in the same way as in Example 3 into a vibrating drum for dry barrel polishing, and use a short rod-shaped lead rod with a diameter of 1 mm and a length of 1 mm to form a fine lead on the surface of the bonded magnet. For the conductive layer composed of fragments, the indentation thickness of the lead fragments on the resin surface is about 0.9 μm, and the coating thickness on the surface of the magnetic powder is 0.6 μm. The conditions during barrel polishing were the same as in Example 1.

Then copper and nickel were electroplated under the same conditions as in Example 3, and the annular bonded magnet thus treated was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 500 hours. After the moisture resistance test, the performance of the magnet is shown in Table 5, and the surface state and film thickness dimensional accuracy after the moisture resistance test are shown in Table 6. Comparative example 6

The ring-shaped bonded magnet produced by the same method as in Example 3 was cleaned, and electroless copper plating was performed on it, and the thickness of the plating layer was 5 μm. After electroless copper plating, under the same condition as embodiment 3, electroplate copper and nickel, carry out environmental test (moisture resistance test) with the ring-shaped bonded magnet after processing like this, 80 ℃ of temperatures, relative humidity 90%, test time 500 hours . After the moisture resistance test, the performance of the magnet is shown in Table 5, and the surface state and film thickness dimensional accuracy after the moisture resistance test are shown in Table 6. Electroless copper plating process conditions are the same as Comparative Example 1. Comparative example 7

Clean the annular bonded magnet made in the same way as in embodiment 3, form a 10 μm thick conductive film layer on its surface with a mixture of phenolic resin and nickel powder, then electroplate copper and nickel under the same conditions as in embodiment 3, The annular bonded magnet thus treated was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 500 hours. After the moisture resistance test, the performance of the magnet is shown in Table 5, and the surface state and film thickness dimensional accuracy after the moisture resistance test are shown in Table 6. Electroless copper plating process conditions are the same as Comparative Example 2. Comparative example 8

Clean the annular bonded magnet made in the same way as in Example 3, form a layer of phenolic resin bonding layer on its surface by dipping, then adhere silver powder (particle size 0.7 μm or lower) on its surface, and then use A vibrating drum was used to form a 7 μm thick conductive film layer, and then copper and nickel were electroplated under the same conditions as in Example 3. The annular bonded magnet thus treated was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 500 hours. After the moisture resistance test, the performance of the magnet is shown in Table 5, and the surface state and film thickness dimensional accuracy after the moisture resistance test are shown in Table 6. The process conditions of electroless copper plating are the same as in Comparative Example 3. table 5 Before moisture resistance test After moisture resistance test Magnetic property reduction ratio (%) Br(kG) ihc(kOe) (BH)max(MGOe) Br(kG) iHc(kOe) (BH)max(MGOe) Br(kG) iHc(kOe) (BH)max(MGOe) Example 3 6.7 9.0 9.0 6.7 8.9 9.0 2.8 2.2 3.2 Example 4 6.7 9.0 9.0 6.7 8.8 9.0 2.8 3.2 3.2 Example 5 6.7 9.0 9.0 6.6 8.8 8.9 4.4 3.3 4.3 Comparative example 6 6.5 8.7 8.8 5.8 7.6 7.7 15.9 16.5 17.2 Comparative example 7 6.5 8.9 8.9 6.2 8.4 8.5 10.1 7.7 8.6 Comparative example 8 6.5 8.9 9.0 6.2 8.5 8.5 10.1 6.6 8.6 Magnetic property reduction ratio (%)=[{(initial magnetic property)-(magnetic property after moisture resistance test)}/(initial magnetic property)]×100 Table 6 Surface state after a certain moisture resistance test time Dimensional accuracy of film thickness (μm) Manufacturing method Example 3 No change (no rust) 22±1 Sn coating + Cu, Ni plating Example 4 No change (no rust) 22±1 Zn coating + Cu, Ni plating Example 5 No change (no rust) 22±1 Pb coating + Cu, Ni plating Comparative example 6 Pitting corrosion occurs after 130h 26±2 Electroless copper plating + Cu, Ni plating Comparative example 7 A small amount of rust appeared after 250h 32±9 Resin conductive layer + Cu, Ni plating Comparative example 8 A small amount of rust appeared after 330h 28±10 Conductive film + Cu, Ni plating Can be seen from Table 5～6: comparative example 6 after about 130 hours, comparative example 7 after 250 hours, comparative example 8 takes place spot corrosion after 330 hours; No spot rust was observed.

Example 6

The ring-shaped bonded magnet of 34mm (outer diameter) × 31mm (inner diameter) × 8mm (height) was manufactured by the same method as in Example 1, and its properties are as follows: Br=6.7kG, iHc=9.1kOe, (BH) _max =9.1MGOe.

Put the bonded magnet above into a vibrating drum and use Al ₂ O ₃ spherical drum abrasives with an average diameter of 3mm for sealing and finishing treatment. Its processing condition and using method are with embodiment 2.

Then put the above-mentioned bonded magnet into a vibrating roller for dry-process roller polishing, using short rod-shaped tin, zinc and lead rods with a diameter of 1mm and a length of 1mm to form a conductive layer composed of fine metal fragments on the surface of the bonded magnet, Table 7 shows the indentation depth of fine metal fragments on the surface of the resin and the porous part and the thickness of the coating layer on the surface of the magnetic powder. The conditions during barrel polishing were the same as in Example 2.

Then it is cleaned, and copper is electroplated with a hanger-type electroplating device, and then nickel is electroplated. After electroplating, the coating thickness is 21 μm at the inner diameter and 22 μm at the outer diameter. The annular bonded magnet thus treated was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 1000 hours. The test results and the dimensional accuracy of the film thickness are shown in Table 8 and Table 9. The process condition when electroplating copper and nickel is the same as embodiment 2. Comparative example 9

The annular bonded magnet obtained by the same method as in Example 6 was cleaned, then sealed and surface finished in the same way as in Example 6, cleaned again, and then electroless copper-plated with a thickness of 5 μm. Copper plating and nickel plating were carried out under the same conditions as in Example 6 after electroless copper plating.

The annular bonded magnet after the treatment in this way is carried out environmental test (moisture resistance test) under the same condition as embodiment 6, the magnetic properties before and after the moisture resistance test are shown in Table 8, and the surface condition and film after the moisture resistance test The dimension accuracy of layer thickness is shown in Table 9. The process conditions of electroless copper plating are the same as those of comparative example 4. Comparative example 10

Clean the ring-shaped bonded magnet obtained in the same way as in Example 6, and then use a mixture of phenolic resin and nickel powder to form a 10 μm thick conductive resin coating on the surface of the magnet, and then put it into a vibrating drum to account for 60% of its volume. % of magnets and 5mm steel balls, under the condition of an amplitude of 20mm, barrel polishing was carried out for 60 minutes to finish and polish.

Then electroplated copper and electroplated nickel under the same conditions as in Example 6, the ring-shaped bonded magnet after such processing is carried out under the same conditions as in Example 6. Environmental test (moisture resistance test), its test results and film thickness See Table 8 and Table 9 for dimensional accuracy. The treatment conditions of the conductive coating layer are the same as those of Comparative Example 5. Table 7 metal shards Indentation depth of resin surface and porous part (μm) Coating thickness on magnetic powder surface (μm) sn 0.9 0.4 Zn 0.7 0.3 Pb 0.9 0.5 Table 8 Before moisture resistance test After moisture resistance test Magnetic property reduction ratio (%) Br(kG) iHc(kOe) (BH) _max (MGOe) Br(kG) iHc(kOe) (BH) _max (MGOe) Br(kG) iHc(kOe) (BH) _max (MGOe) Example 6Sn 6.6 9.0 9.0 6.4 8.6 8.6 4.5 5.5 5.5 Example 6Zn 6.6 9.0 9.0 6.3 8.6 8.6 6.0 5.5 5.5 Example 6Pb 6.6 9.0 9.0 6.3 8.5 8.5 6.0 6.6 6.6 Comparative example 9 6.6 8.9 9.0 6.2 8.4 8.3 7.5 7.7 8.8 Comparative example 10 6.6 9.0 9.0 6.0 8.2 8.1 10.4 9.9 11.0 Magnetic property reduction ratio (%)=[{(initial magnetic property)-(magnetic property after moisture resistance test)}/(initial magnetic property)]×100 Table 9 Surface state after moisture resistance test Dimensional accuracy of film thickness (μ m) Manufacturing method Example 6Sn No change (no rust) 22±1 Sealing treatment+Sn film layer+Cu, Ni plating layer Example 6Zn No change (no rust) 22±1 Sealing treatment+Zn film layer+Cu, Ni plating layer Example 6Pb No change (no rust) 22±1 Sealing treatment+Pb film layer+Cu, Ni plating layer Comparative example 9 Pitting corrosion occurs after 800h 27±2 Sealing treatment + electroless copper plating + Cu, Ni plating Comparative example 10 Pitting corrosion occurs after 600h 30±5 Resin conductive layer + finishing and polishing + Cu, Ni plating

As can be seen from Table 9: comparative example 9 after about 800 hours, comparative example 10 after 600 hours all occurs point corrosion; There is some rust.

Example 7

The ring-shaped bonded magnet of 21mm (outer diameter) × 18mm (inner diameter) × 4mm (height) was manufactured by the same method as Example 1, and its properties are listed in Table 11: Br=6.8kG, iHc=9.1kOe, ( BH) _max = 9.2MGOe.

Put the above bonded magnet into a vibrating drum for dry drum polishing, use short rod-shaped Fe, Ni, Co and Cr rods with a diameter of 0.7 mm and a length of 0.5 mm to form these fine metal particles on the surface of the bonded magnet. The conductive coating layer composed of fragments, the indentation depth of the fine metal fragments on the resin surface and the coating layer thickness on the magnetic powder surface are shown in Table 10. The conditions during barrel polishing were the same as in Example 1.

Then it is cleaned, and copper is electroplated with a hanger-type electroplating device, and then nickel is electroplated. After electroplating, the coating thickness is 18 μm at the inner diameter and 21 μm at the outer diameter. The annular bonded magnet thus treated was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 500 hours. The performance of the magnet after the moisture resistance test is shown in Table 12, and the surface condition and film thickness dimensional accuracy after the moisture resistance test are shown in Table 13. The process conditions during electroplating copper and electroplating nickel are the same as embodiment 1. Comparative example 11

The ring-shaped bonded magnet obtained in the same manner as in Example 7 was cleaned and then electroless copper-plated with a thickness of 6 μm. After electroless copper plating, copper and nickel were electroplated under the same conditions as in Example 3. The annular bonded magnet thus treated was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 500 hours. See Table 12 for the magnetic properties of the magnet after the moisture resistance test, and Table 13 for the surface condition and film thickness dimensional accuracy after the moisture resistance test. The process conditions of electroless copper plating are the same as in Comparative Example 1. Comparative example 12

Clean the ring-shaped bonded magnet obtained in the same way as in Example 7, and then form a 10 μm thick conductive coating on the surface of the magnet with a mixture of phenolic resin and nickel powder. Copper and nickel plating under conditions. The annular bonded magnet thus treated was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 500 hours. See Table 12 for the magnetic properties of the magnet after the moisture resistance test, and Table 13 for the surface condition and film thickness dimensional accuracy after the moisture resistance test. The formation conditions of the resin conductive coating layer are the same as those of Comparative Example 2. Comparative example 13

Clean the ring-shaped bonded magnet obtained in the same way as in Example 7, form a layer of phenolic resin adhesive layer on its surface by dipping, then adhere silver powder (particle size 0.7 μm or lower) on its surface, and then in A conductive film layer with a thickness of 7 μm was formed in a vibrating drum, and then copper and nickel were electroplated under the same conditions as in Example 7. The annular bonded magnet thus treated was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 500 hours. After the moisture resistance test, the performance of the magnet is shown in Table 12, and the surface state and film thickness dimensional accuracy during the moisture resistance test are shown in Table 13. The process conditions of electroless copper plating are the same as in Comparative Example 3. Table 10 metal shards Indentation depth of resin surface and porous part (μm) Coating thickness on magnetic powder surface (μm) Fe 0.5 0.1 Ni 0.4 0.1 co 0.3 0.1 Cr 0.3 0.1 Table 11 Starting material magnetic properties Br(kG) iHc(kOe) (BH) _max (MGOe) Example 7 Fe 6.8 9.1 9.2 Example 7 Ni 6.8 9.1 9.2 Example 7 Co 6.8 9.1 9.2 Example 7 Cr 6.8 9.1 9.2 Comparative example 11 6.8 9.1 9.2 Comparative example 12 6.8 9.1 9.2 Comparative example 13 6.8 9.1 9.2 Table 12 Before moisture resistance test After moisture resistance test Magnetic property reduction ratio (%) Br(kG) iHc(kOe) (BH) _max (MGOe) Br(kG) iHc(kOe) (BH) _max (MGOe) Br(kG) ikB (BH) _max (MGOe) Example 7 Fe 6.7 9.0 9.0 6.4 8.7 8.7 5.9 4.4 5.5 Example 7 Ni 6.7 9.0 9.0 6.4 8.7 8.7 5.9 4.4 5.5 Example 7 Co 6.7 9.0 9.0 6.4 8.6 8.7 5.9 5.5 5.5 Example 7 Cr 6.7 9.0 9.0 6.4 8.6 8.6 5.9 5.5 6.6 Comparative example 11 6.4 8.7 8.7 5.7 7.7 7.7 16.2 15.4 16.3 Comparative example 12 6.6 8.9 9.0 6.3 8.5 8.5 7.4 6.6 7.6 Comparative example 13 6.6 9.0 9.0 6.3 8.4 8.5 7.4 7.7 7.6 Magnetic property reduction ratio (%)=[{(initial magnetic property)-(magnetic property after moisture resistance test)}/(initial magnetic property)]×100 Table 13 Surface state after moisture resistance test Dimensional accuracy of film thickness (μm) Manufacturing method Example 7 Fe No change (no rust) 18±2 Fe coating + Ni plating Example 7 Ni No change (no rust) 18±2 Ni coating + Ni plating Example 7 Co No change (no rust) 18±2 Co coating + Ni plating Example 7 Cr No change (no rust) 18±2 Pb coating + Ni plating Comparative example 11 Pitting corrosion occurs after 130h 24±2 Electroless copper plating layer+Ni plating layer Comparative example 12 Pitting corrosion occurs after 350h 28±10 Resin conductive layer + Ni plating Comparative example 13 Pitting corrosion occurs after 370h 25±10 Resin conductive layer + Ni plating

As can be clearly seen from Tables 10 to 13: comparative example 11 after about 130 hours, comparative example 12 after about 350 hours, comparative example 13 after about 370 hours, all appear point rust; and on the other hand, for embodiment 7, Even after 500 hours, there is no spot rust under a 30X microscope.

Example 8

The annular bonded magnet of 29mm (outer diameter) × 25mm (inner diameter) × 5mm (height) was manufactured by the same method as in Example 1, and its properties are listed in Table 15: Br=6.7kG, iHc=9.3kOe, ( BH) _max = 9.5MGOe.

Put the bonded magnet above into a vibrating drum and use Al ₂ O ₃ spherical drum abrasives with an average diameter of 3mm for sealing and finishing treatment. Its processing condition and using method are with embodiment 2.

Then put the above-mentioned bonded magnet into a vibrating roller for dry roller polishing, using short rod-shaped Fe, Ni, Co and Cr rods with a diameter of 0.5mm and a length of 0.4mm to form fine metal particles on the surface of the bonded magnet. Table 14 shows the conductive layer composed of fragments, the indentation depth of fine metal fragments on the resin surface and the porous part, and the coating layer thickness on the surface of the magnetic powder. The conditions during barrel polishing were the same as in Example 2.

This is followed by cleaning and nickel plating with a hanger-type plating device, followed by nickel plating. After electroplating, the coating thickness is 20 μm at the inner diameter and 22 μm at the outer diameter. The annular bonded magnet thus treated was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 1000 hours. See Table 16 and Table 17 for the test results and the dimensional accuracy of the film thickness.

The process condition of electroplating copper and nickel is the same as embodiment 2. The technical conditions of zinc replacement treatment are as follows: treatment time 40 seconds, bath temperature 22°C, bath composition: 300g/l sodium hydroxide, 40g/l zinc oxide, 1g/l ferric chloride, 30g/l Rossel salt. The film thickness is 0.01 μm. Comparative example 14

The ring-shaped bonded magnet obtained by the same method as in Example 8 was cleaned, followed by the same sealing and surface finishing treatment as in Example 6, cleaned again, and then electroless copper plating was performed on it, with a coating thickness of 5 μm. Electroless copper plating and nickel electroplating were performed under the same conditions as in Example 8 after electroless copper plating.

The annular bonded magnet treated in this way was subjected to an environmental test (moisture resistance test) under the same conditions as in Example 8. The test results and the dimensional accuracy of the film thickness are shown in Table 16 and Table 17. The process conditions of electroless copper plating are the same as those of comparative example 4. Comparative example 15

Clean the ring-shaped bonded magnet obtained in the same way as in Example 6, and then use a mixture of phenolic resin and nickel powder to form a 10 μm thick conductive resin coating on the surface of the magnet, and then put it into a vibrating drum to account for 60% of its volume. % of magnets and 5mm steel balls, under the condition of an amplitude of 20mm, barrel polishing was carried out for 60 minutes to finish and polish.

Then electroplated copper and electroplated nickel under the same conditions as in Example 8, the ring-shaped bonded magnet after such processing is carried out under the same conditions as in Example 6 for environmental testing (moisture resistance test), its test results and film thickness See Table 16 and Table 17 for dimensional accuracy. The treatment conditions of the conductive coating layer are the same as those of Comparative Example 5. Table 14 metal shards Indentation depth of resin surface and porous part (μm) Coating thickness on magnetic powder surface (μm) Fe 0.5 0.1 Ni 0.5 0.1 co 0.4 0.1 Cr 0.4 0.1 Table 15 Starting material magnetic properties Br(kG) iHc(kOe) (BH) _max (MGOe) Example 8 Fe 6.9 9.3 9.5 Example 8 Ni 6.9 9.3 9.5 Example 8 Co 6.9 9.3 9.5 Example 8 Cr 6.9 9.3 9.5 Comparative example 14 6.9 9.3 9.5 Comparative example 15 6.9 9.3 9.5 Table 16 Before moisture resistance test After moisture resistance test Magnetic property reduction ratio (%) Br(kG) iHc(kOe) (BH) _max (MGOe) Br(kG) iHc(kOe) (BH) _max (MGOe) Br(kG) iHc(kOe) (BH) _max (MGOe) Example 8 Fe 6.7 9.2 9.4 6.6 8.9 9.0 4.3 4.3 5.3 Example 8 Ni 6.7 9.2 9.4 6.5 8.9 8.9 5.8 4.3 6.3 Example 8 Co 6.6 9.2 9.4 6.4 8.8 8.8 7.2 5.4 7.4 Example 8 Cr 6.7 9.2 9.4 6.5 8.7 8.8 5.8 6.5 7.4 Comparative example 14 6.6 9.1 9.3 6.2 8.5 8.5 10.1 8.6 10.5 Comparative example 15 6.7 9.1 9.3 6.2 8.3 8.4 10.1 10.8 11.6 Magnetic property reduction ratio (%)=[{(initial magnetic property)-(magnetic property after moisture resistance test)}/(initial magnetic property)]×100 Table 17 Surface state after moisture resistance test Dimensional accuracy of film thickness (μm) Manufacturing method Example 8 Fe No change (no rust) 20±2 Sealing treatment + Fe coating + Ni plating Example 8 Ni No change (no rust) 20±2 Sealing treatment + Ni coating + Ni plating Example 8 Co No change (no rust) 20±2 Sealing treatment+Co coating layer+Ni plating layer Example 8 Cr No change (no rust) 20±2 Sealing treatment+Cr coating layer+Ni plating layer Comparative example 14 Pitting corrosion occurs after 700h 25±2 Sealing treatment + electroless copper plating layer + Ni plating layer Comparative example 15 Pitting corrosion occurs after 550h 26±5 Resin conductive layer + finishing and polishing + Ni plating

As can be seen from Table 17: comparative example 14 all occurs spot corrosion after 700 hours, comparative example 15 after 550 hours; And on the other hand, for embodiment 8, even through 800 hours, also do not appear under 30 times microscope Spot rust.

Example 9

The annular bonded magnet of 20mm (outer diameter) × 17mm (inner diameter) × 6mm (height) was manufactured by the same method as in Example 1, and its performance is as follows: Br=6.9kG, iHc=9.4kOe, (BH) _max =9.6MGOe.

The above-mentioned bonded magnet was put into a vibrating roller for dry roller polishing, and a short rod-shaped aluminum rod with a diameter of 0.8mm and a length of 1mm was used to form a conductive coating composed of fine aluminum fragments on the surface of the bonded magnet. The indentation depth of the fine metal fragments is about 0.9 μm, and the thickness of the coating layer on the surface of the magnetic powder is 0.5 μm. The conditions during barrel polishing were the same as in Example 1.

Then cleaning is performed, zinc replacement treatment is performed, and then nickel plating is performed with a hanger type plating device, and then nickel plating is performed. After electroplating, the coating thickness is 19 μm at the inner diameter and 21 μm at the outer diameter. The annular bonded magnet thus treated was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 500 hours. The performance of the magnet after the moisture resistance test is shown in Table 18, and the surface condition and film thickness dimensional accuracy after the moisture resistance test are shown in Table 19. The process condition during electroplating nickel is with embodiment 1. Comparative example 16

The ring-shaped bonded magnet obtained in the same manner as in Example 9 was cleaned, and then electroless copper plating was performed on it with a plating thickness of 6 μm. After electroless copper plating, copper and nickel were electroplated under the same conditions as in Example 3. The annular bonded magnet thus treated was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 500 hours. See Table 18 for the magnetic properties of the magnet after the moisture resistance test, and Table 19 for the surface condition and film thickness dimensional accuracy after the moisture resistance test. The process conditions of electroless copper plating are the same as in Comparative Example 1. Comparative example 17

Clean the ring-shaped bonded magnet obtained in the same way as in Example 9, and then form a 10 μm thick conductive coating on the surface of the magnet with a mixture of phenolic resin and nickel powder. Nickel plating under conditions. The annular bonded magnet thus treated was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 500 hours. See Table 18 for the magnetic properties of the magnet after the moisture resistance test, and Table 19 for the surface condition and film thickness dimensional accuracy after the moisture resistance test. The formation conditions of the resin conductive coating layer are the same as those of Comparative Example 2. Comparative example 18

Clean the ring-shaped bonded magnet obtained in the same way as in Example 9, form a layer of phenolic resin adhesive layer on its surface by dipping, then adhere silver powder (particle size 0.7 μm or lower) on its surface, and then in A conductive film layer with a thickness of 7 μm was formed in a vibrating drum, and then nickel was electroplated under the same conditions as in Example 9. The annular bonded magnet thus treated was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 500 hours. After the moisture resistance test, the performance of the magnet is shown in Table 18, and the surface state and film thickness dimensional accuracy after the moisture resistance test are shown in Table 19. The process conditions for coating formation are the same as in Comparative Example 3. Table 18 Before moisture resistance test After moisture resistance test Magnetic property reduction ratio (%) Br(kG) iHc(kOe) (BH) _max (MGOe) Br(kG) iHc(kOe) (BH) _max (MGOe) Br(kG) iHc(kOe) (BH) _max (MGOe) Example 9 6.7 9.0 9.2 6.4 8.8 9.0 7.2 6.4 6.3 Comparative example 16 6.4 8.7 8.9 5.7 7.9 8.0 17.4 16.0 16.7 Comparative example 17 6.6 8.9 9.3 6.2 8.6 8.7 10.1 8.5 9.4 Comparative example 18 6.6 9.0 9.2 6.2 8.6 8.7 10.1 8.5 9.4 Magnetic property reduction ratio (%)=[{(initial magnetic property)-(magnetic property after moisture resistance test)}/(initial magnetic property)]×100 Table 19 Surface state after moisture resistance test Dimensional accuracy of film thickness (μm) Manufacturing method Example 9 No change (no rust) 20±2 Al coating (zinc replacement treatment) + Ni plating Comparative example 16 Pitting corrosion occurs after 120h 27±2 Electroless copper plating layer+Ni plating layer Comparative example 17 Slight corrosion after 270h 28±10 Resin conductive coating + Ni plating Comparative example 18 Slight corrosion after 300h 26±10 Conductive coating + Ni plating

From Table 18 and Table 19, it can be clearly seen that: comparative example 16 after about 120 hours, comparative example 17 after about 270 hours, comparative example 18 after about 300 hours, spot corrosion all occurs; and on the other hand, for embodiment 9 , even after 500 hours, there is no point rust under a 30X microscope.

Example 10

The ring-shaped bonded magnet of 36mm (outer diameter) × 33mm (inner diameter) × 3mm (height) was manufactured by the same method as Example 1, and its properties are as follows: Br=6.7kG, iHc=9.2kOe, (BH) _max =9.5MGOe.

Put 220 such magnets together with spherical Al ₂ O ₃ drum abrasives with an average diameter of 4 mm into a vibrating drum with a volume of 20 liters, and fill in 50% of the drum volume with plant-derived materials, and the plant-derived materials are the surface Walnut kernels with a diameter of approximately 2 mm that had been modified with Al ₂ O ₃ with a particle size of approximately 2 μm were then subjected to dry surface polishing for 150 minutes to seal voids and finish.

Next, put the magnet into a vibrating drum for dry drum polishing, and use a short rod-shaped aluminum rod with a diameter of 0.5 mm and a length of 0.7 mm to form a conductive layer composed of fine aluminum fragments on the surface of the bonded magnet. The depth of pressing into the resin surface is about 1.1 μm, and the coating thickness on the surface of the magnetic powder is 0.6 μm. The conditions of the barrel polishing treatment were the same as in Example 1.

Then cleaning, zinc replacement treatment, and nickel plating with a hanger type plating device, followed by nickel plating. After electroplating, the coating thickness is 17 μm at the inner diameter and 19 μm at the outer diameter. The annular bonded magnet thus treated was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 500 hours. The performance of the magnet after the moisture resistance test is shown in Table 20, and the surface condition and film thickness dimensional accuracy after the moisture resistance test are shown in Table 21.

The process condition of electroplating copper and nickel is the same as embodiment 2. The technical conditions of zinc replacement treatment are as follows: treatment time 40 seconds, bath temperature 22°C, bath composition: 300g/l sodium hydroxide, 40g/l zinc oxide, 1g/l ferric chloride, 30g/l Rossel salt. The thickness of the zinc replacement layer is 0.01 μm. Comparative example 19

Clean the annular bonded magnet made by the same method as in Example 10, seal it and finish the surface according to Example 10, clean it again, and then perform electroless copper plating on it, with a thickness of 6 μm. After electroless copper plating, copper and nickel were electroplated under the same conditions as in Example 10. The annular bonded magnet thus treated was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 1000 hours. See Table 20 for the magnetic properties of the magnet after the moisture resistance test, and Table 21 for the surface condition and film thickness dimensional accuracy after the moisture resistance test. The process conditions of electroless copper plating are the same as those of comparative example 4. Comparative example 20

The annular bonded magnet produced in the same manner as in Example 10 was cleaned, and then a conductive coating layer of 12 µm thick was formed on the surface of the magnet with a mixture of phenolic resin and nickel powder under the following conditions. Then, the above-mentioned magnets and 2mm steel balls, which account for 70% of the volume, were loaded into the vibrating drum, and the drum polishing was carried out for 90 minutes to finish and polish.

Then nickel was electroplated under the same process conditions as in Example 10. The annular bonded magnet thus treated was subjected to an environmental test (moisture resistance test) at a temperature of 80° C., a relative humidity of 90%, and a test time of 1000 hours. The performance of the magnet after the moisture resistance test is shown in Table 20, and the surface condition and film thickness dimensional accuracy after the moisture resistance test are shown in Table 21. The process conditions of electroless copper plating are the same as those of Comparative Example 5. Table 20 Before moisture resistance test After moisture resistance test Magnetic property reduction ratio (%) Br(kG) iHc(kOe) (BH) _max (MGOe) Br(kG) iHc(kOe) (BH) _max (MGOe) Br(kG) iHc(kOe) (BH) _max (MGOe) Example 10 6.5 9.0 9.2 6.4 8.7 9.0 4.5 5.4 5.3 Comparative example 19 6.4 8.7 8.9 6.0 8.3 8.5 10.5 9.8 10.5 Comparative example 20 6.4 8.9 9.3 6.1 8.4 8.5 9.0 8.7 10.5 Magnetic property reduction ratio (%)=[((initial magnetic property)-(magnetic property after moisture resistance test)}/(initial magnetic property)]×100 Table 21 Surface state after moisture resistance test Dimensional accuracy of film thickness (μm) Manufacturing method Example 10 No change (no rust) 18±2 Sealing treatment + Al coating (zinc replacement treatment) + Ni plating Comparative example 19 Pitting corrosion occurs after 750h 24±2 Sealing treatment + electroless copper plating + Ni plating Comparative example 20 Pitting corrosion occurs after 680h 28±6 Resin conductive coating + finishing and polishing + Ni plating From Table 20 and Table 21, it can be clearly seen that: after about 750 hours, Comparative Example 19 and Comparative Example 20 have spot corrosion after 680 hours; There is no point of rust under the microscope.

industrial application

In the present invention, the porous R-Fe-B bonded magnet is subjected to dry barrel polishing, wherein a mixture of a polishing agent and a plant-derived material is used as a polishing medium, or, after the polishing agent and the surface has been modified by an inorganic powder A mixture of plant-derived materials is used as a polishing medium. Polishing powder, inorganic powder, and polishing shavings can be stuck on the R-Fe-B-based bonded magnet with oily components in plant-derived materials to fill the porous portion thereof. Bonded magnets can also be improved while performing surface finishing treatments. In addition, R-Fe-B based bonded magnets are subjected to dry roller polishing in a roller device, and aluminum blocks of required size and indeterminate shape such as spherical, block or needle-shaped (linear) are used as metal media to make aluminum grinding The crushed fine fragments are pressed into the porous part of the surface of the bonded magnet and the surface of the resin to form a film layer, or the surface of the magnetic powder is coated with aluminum fine fragments to form a layer of aluminum on the surface of the R-Fe-B based bonded magnet coating layer, followed by zinc replacement treatment on the surface of the aluminum coating layer, so that a dense, pinhole-free electroplating layer can be formed, and an R-Fe-B based bonded magnet with excellent corrosion resistance can be obtained.

Claims (18)

1. a high corrosion-resistant R-Fe-B base bonded magnet is characterized in that the fine metal fragment is pressed into and is coated in resin surface and the porousness part that constitutes this R-Fe-B base bonded magnet surface; And this R-Fe-B base bonded magnet comprises the layer of metal clad surface, it is to apply the Magnaglo surface that constitutes described surface by the metal superfine fragment to form, and at the most surperficial formation electrodeposited coating of magnet, thereby the surface of described washing is between the two.

2. high corrosion-resistant R-Fe-B base bonded magnet, it is characterized in that sealing porousness part in the described R-Fe-B base bonded magnet surface with polishing agent powder, bonded permanent magnet buffing or the inorganic powder that also is bonded in it with the oily components in the vegetable-derived materials, the fine metal fragment is pressed into and is coated in resin surface and the described porousness part that constitutes this magnet surface; Its feature is that also this R-Fe-B base bonded magnet comprises the layer of metal clad surface, it is to apply the Magnaglo surface that constitutes magnet surface by the metal superfine fragment to form, and at the most surperficial one deck electrodeposited coating that also forms of magnet, thereby described surface metal coat is between the two.

3. according to the high corrosion-resistant R-Fe-B base bonded magnet of claim 1 or claim 2, it is characterized in that this fine metal fragment is Cu, Sn, Zn, Pb, Cd, In, Au, Ag, Fe, Ni, Co, Cr or Al, or the alloy of above element.

4. according to the high corrosion-resistant R-Fe-B base bonded magnet of claim 1 or claim 2, it is characterized in that the fine metal fragment is 0.1 μ m～2 μ m at the coating thickness that is pressed into that resin surface and porousness partly form.

5. according to the high corrosion-resistant R-Fe-B base bonded magnet of claim 1 or claim 2, it is characterized in that the fine metal fragment is 1.0 μ m or lower at the coating thickness that the Magnaglo surface forms.

6. according to the high corrosion-resistant R-Fe-B base bonded magnet of claim 5, it is characterized in that Cu, Fe, Ni, Co or Cr or their the alloy coating thickness on the Magnaglo surface is 0.2 μ m or lower.

7. according to the high corrosion-resistant R-Fe-B base bonded magnet of claim 1 or claim 2, it is characterized in that when above-mentioned fine metal fragment is aluminum or aluminum alloy, on the aluminum or aluminum alloy clad surface of described magnet surface, form a middle zinc layer, form electrodeposited coating again.

8. the manufacture method of a high corrosion-resistant R-Fe-B base bonded magnet, it is characterized in that comprising the following step: the fine metal sheet of R-Fe-B base bonded magnet and indefinite shape is packed in the drum apparatus, carry out the dry method tumbling, the fine metal fragment that grinds can be pressed into resin surface and the porousness part that constitutes R-Fe-B base bonded magnet surface, form coating, and the Magnaglo surface that constitutes this magnet surface has also applied the above-mentioned fine metal fragment of one deck, thereby, then utilize the plating outmost surface pressing formation one deck electrodeposited coating on this conductive metal coating of above-mentioned formation at this magnet surface formation layer of metal coat.

9. the manufacture method of a high corrosion-resistant R-Fe-B base bonded magnet, it is characterized in that comprising the following step: the R-Fe-B base bonded magnet is carried out the dry method tumbling, done polishing medium by the mixture of the vegetable-derived materials after the inorganic powder modification with polishing agent and vegetable-derived materials or its surface, with polishing agent powder, bonded permanent magnet buffing or also seal the porousness part on described R-Fe-B bonded permanent magnet surface with the inorganic powder of the bonding of the oily components in the vegetable-derived materials, and finishing and improve its surface; In the fine metal sheet and the drum apparatus of packing into this bonded permanent magnet and indefinite shape, carry out the dry method tumbling, so that the fine metal fragment that grinds can be pressed into the resin surface and the described porousness part of this magnet surface, form coating, and the Magnaglo surface of this magnet surface also applied one deck fine metal fragment, thereby makes the surface of this R-Fe-B base bonded magnet have conductivity; Follow the most surperficial formation one deck electrodeposited coating at magnet.

10. according to Claim 8 or the high corrosion-resistant R-Fe-B base bonded magnet manufacture method of claim 9, it is characterized in that this fine metal fragment is Cu, Sn, Zn, Pb, Cd, In, Au, Ag, Fe, Ni, Co, Cr or Al, or the alloy of above element.

11. according to Claim 8 or the high corrosion-resistant R-Fe-B base bonded magnet manufacture method of claim 9, it is characterized in that when above-mentioned fine metal fragment is aluminium, on the surface of the aluminium coating of described magnet surface, form one with the zinc replacement Treatment in the middle of the zinc layer, form electrodeposited coating again.

12. according to Claim 8 or the high corrosion-resistant R-Fe-B base bonded magnet manufacture method of claim 9, the fine metal sheet that it is characterized in that this indefinite shape is spherical, piece shape or aciculiform, and size is 0.1mm～10mm.

13. according to the high corrosion-resistant R-Fe-B base bonded magnet manufacture method of claim 12, it is characterized in that Cu, Fe, Ni, Co or the Cr fine metal sheet of this indefinite shape is sphere, piece shape or aciculiform, size is 0.1mm～5mm.

14. according to Claim 8 or the high corrosion-resistant R-Fe-B base bonded magnet manufacture method of claim 9, it is characterized in that the fine metal chip length that tumbling grinds is 5 μ m or littler.

15. according to Claim 8 or the high corrosion-resistant R-Fe-B base bonded magnet manufacture method of claim 9, use rotary, oscillatory type or centrifugal cylinder when it is characterized in that tumbling, the volume ratio of above-mentioned magnet and above-mentioned fine metal fragment (magnet/fine metal fragment) is 3 or lower.

16., it is characterized in that polishing agent is Metal Ball or the inorganic powder polish abrasive firing and harden according to the high corrosion-resistant R-Fe-B base bonded magnet manufacture method of claim 9.

17., it is characterized in that above-mentioned vegetable-derived materials is plant shell, wood chip, pericarp or maize cob according to the high corrosion-resistant R-Fe-B base bonded magnet manufacture method of claim 9.

18. according to Claim 8 or the high corrosion-resistant R-Fe-B base bonded magnet manufacture method of claim 9, it is characterized in that above-mentioned R-Fe-B base bonded magnet and above-mentioned fine metal fragment carry out the dry method tumbling under inert gas atmosphere.