CN1131530C - Process for mfg. Fe-B-R based permanent magnet with corrosion-resisting film - Google Patents

Process for mfg. Fe-B-R based permanent magnet with corrosion-resisting film Download PDF

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CN1131530C
CN1131530C CN99118336.3A CN99118336A CN1131530C CN 1131530 C CN1131530 C CN 1131530C CN 99118336 A CN99118336 A CN 99118336A CN 1131530 C CN1131530 C CN 1131530C
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film
metal
magnet
oxide film
metal oxide
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CN1249520A (en
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西内武司
吉村公志
菊井文秋
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Proterial Ltd
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Sumitomo Special Metals Co Ltd
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Abstract

An Fe-B-R based permanent magnet has a metal oxide film having a thickness of 0.01 mu m to 1 mu m on its surface with a metal film interposed therebetween. Thus, the film is excellent in adhesion to the surface of the magnet. Even if the permanent magnet is left to stand under high-temperature and high-humidity of a temperature of 80 DEG C and a relative humidity of 90 % for a long period of time, the magnetic characteristic of the magnet cannot be degraded. The magnet has a thermal shock resistance enough to resist even a heat cycle for a long period of time in a temperature range of -40 DEG C to 85 DEG C, and can exhibit a stable high magnetic characteristic. Therefore, it is possible to produce an Fe-B-R based permanent magnet having a corrosion-resistant film free from hexa-valent chromium.

Description

Manufacturing process with Fe-B-R base permanent magnet of corrosion-resisting film
Invention field
The present invention relates to have the manufacturing process of Fe-B-R base permanent magnet of the corrosion-resisting film of excellent properties.More specifically, the present invention relates to have on its surface manufacturing process with the Fe-B-R base permanent magnet of the excellent in resistance corrosive film of the good adhesion of magnet surface, need not to carry out plating and handle and use chromic processing, promptly can low cost easily form corrosion-resisting film, though this magnet have under the high temperature of relative humidity of the temperature that is in 80 ℃ and 90% and the hot conditions also not can deterioration stable high magnetic characteristics.
Background technology
With the Fe-B-Nd base permanent magnet is that the Fe-B-R base permanent magnet of representative is applied to various fields, because it is by the cheap material manufacturing of ABUNDANT NATUREAL RESOURSES, and has high magnetic property.
But the Fe-B-R base permanent magnet is easily oxidized and corrode in atmosphere, because it contains the R and the Fe of very easily reaction.Use is during without the Fe-B-R base permanent magnet of any processing, owing to have small amount of acid, alkali and/or water, thus begin to be corroded and produce iron rust from magnet surface, thus the reduction of magnetic property and discrete caused.And when the magnet that has produced iron rust on it is assembled into device for example in the magnetic circuit time, then iron rust may scatter position or the parts around polluting.
Propose to have on its surface the magnet of corrosion resistant metal plated film already, this is formed by for example electroless plated technology of wet method plating technic and electroplating technology, so that improve the corrosion resistance (the open 3-74012 of visible Japan Patent) of Fe-B-R base permanent magnet by above-mentioned viewpoint.But in this technology, the acidity or the alkaline solution that use in the preliminary treatment before plating is handled may residue in the hole of magnet, thereby magnet is corroded as time passes in some cases.In addition, magnet is poor to the tolerance of chemical substance, so magnet surface may be corroded in the plating processing procedure.In addition, even form metal coating on magnet surface, as mentioned above, if under the condition of 60 ℃ of temperature and 90% humidity magnet is carried out corrosion test, then the magnetic property of magnet can descend 10% from initial value after 100 hours.
Also have a kind of traditional handicraft, wherein on Fe-B-R base permanent magnet surface, form corrosion-resisting film for example phosphate layer or chromate film (the open 4-22008 of visible Japan Patent).The film that this technology forms is being excellent aspect the magnet surface adhesiveness, if but under the condition of 60 ℃ of temperature and 90% humidity, carry out corrosion test, then the magnetic property of magnet can descend 10% from initial value after 300 hours.
In the previous technology that proposes in order to improve Fe-B-R base permanent magnet corrosion resistance, i.e. in so-called chromic acid aluminium treatment process (the open 6-66173 of visible Japan Patent) handles by carrying out chromate after the vapor deposition process formation aluminium film.This technology has improved the corrosion resistance of magnet significantly.But the used chromate of this technology is handled and has been used Cr VI, and this is undesirable for environment, and is therefore complicated to the processing of waste liquid.The film that forms in this technology in the process of processing magnet is troubling to the influence of human body, exactly because it contains a spot of Cr VI.
On the other hand, propose another kind of technology already, wherein on Fe-B-R base permanent magnet surface, form the primary coating layers that forms by metal, and on the primary coating layers surface, form glassy layer (visible Japanese Patent Application Publication 1-165105) as principal component.If use the wet method plating to form primary coating layers, then As time goes on magnet is corroded, as mentioned above.For example, if adopt for example vacuum evaporation technology formation primary coating layers of vapor deposition process, then can provide the magnet that does not have this problem, has excellent anticorrosive.But, in order to carry out vapor deposition process, need large-scale plant, and this device is expensive.Need carry out as pretreated clean magnet surface, in order to form the primary coating layers that is formed by the metal that is easy to oxidation as principal component, these metals for example are aluminium, tin, zinc etc., need high vacuum degree.Reason need vacuumize processing for a long time for this reason, so can not avoid the elongation of the complicated of manufacturing process and manufacturing process required time.
Summary of the invention
Therefore, the object of the present invention is to provide a kind of manufacturing process of Fe-B-R base permanent magnet, on this magnet surface, has excellent in resistance corrosive film with the good adhesion of magnet surface, need not to carry out plating and handle and use chromic processing, promptly can low cost easily form corrosion-resisting film, though this magnet have under the high temperature of relative humidity of the temperature that is in 80 ℃ and 90% and the super-humid conditions also not can deterioration stable high magnetic characteristics.
The inventor has carried out various active research according to above-mentioned viewpoint, found that when Fe-B-R base permanent magnet and metal fragment and put into process tank and, can be deposited on magnet surface from the metal fine powder end that metal fragment produces and form film in the process tank internal vibration and/or when stirring; When utilizing sol-gel technology to form metal oxide film on metal film, the tight adhesion firmly of the metallic film surface on metal oxide film and the magnet has then improved the corrosion resistance of magnet; By using sol-gel technology can reduce influence to human body and environment significantly, and this manufacturing process is very simple.
Finished the present invention based on above-mentioned cognition.In order to realize the present invention, according to first scheme of the present invention and feature, the manufacturing process that has metal oxide film on a kind of its surface, accompanies the permanent magnet of metal film therebetween is provided, comprise following operation, Fe-B-R base permanent magnet and metal fragment are put into process tank, and vibrate therein and/or stir, thereby on magnet surface, form metal film; Metallic film surface is applied by as the hydrolysis of the metallic compound of the parent material of metal oxide film and the sol solution that polymerization reaction generates; With the sol solution that applies is heat-treated, form metal oxide film.
Alternative plan and feature according to the present invention except first feature, use metal fragment to form the metal film of being made by at least a metal ingredient that is selected from aluminium, tin and the zinc.
Third party's case and feature according to the present invention, except first feature, metal fragment is needle-like or column, size (length) is 0.05mm-10mm.
Cubic case and feature according to the present invention, except first feature, thickness of metal film is in the scope of 0.01 μ m-1 μ m.
The 5th scheme and feature according to the present invention, except first feature, sol solution is used to form the metal oxide film of being made by at least a metal oxide composition that is selected from aluminium oxide (Al), silica (Si), zirconia (Zr) and the titanium oxide (Ti).
The 6th scheme and feature according to the present invention, except first feature, sol solution is used to form the metal oxide film that contains the metal ingredient identical with the metal ingredient of metal film.
The 7th scheme and feature according to the present invention, except first feature, the thickness of metal oxide film is in the scope of 0.01 μ m-10 μ m.
All directions case and feature according to the present invention, except first feature, the content of metal oxide film institute carbon containing (C) is in the scope of 50ppm-1000ppm.
The 9th scheme and feature according to the present invention, except first feature, metal oxide film is formed by the metal oxide that is essentially amorphous phase.
According to technology of the present invention, need not to carry out plating and handle or use chromic processing, promptly can low-costly easily form excellent corrosion-resisting film in magnet surface, have excellent and adhesiveness magnet surface, though this magnet can have under the high temperature of relative humidity of the temperature that is in 80 ℃ and 90% and the super-humid conditions also not can deterioration stable high magnetic characteristics.So, the Fe-B-R with excellent anticorrosive can be provided base permanent magnet.
Embodiment
The technology that forms metal film in magnet surface below will be described, comprise Fe-B-R base permanent magnet and metal fragment are put into process tank, and in process tank internal vibration and/or stirring.
Can use the metal fragment corresponding with the metal ingredient of the metal film that is used for requirement.An example of this metal fragment is the metal fragment of being made by at least a metal ingredient that is selected from aluminium, tin, zinc, copper, iron, nickel, cobalt and the titanium.Those that can form metal film in these metal ingredients on sintered magnet effectively are aluminium, tin and zinc.Metal fragment can be made by single metal ingredient or alloy.Use the multiple metal fragment of different metal composition can form the metal film of making by multiple metal ingredient.
Can use the metal fragment with different shape, for example needle-like (wire), column and bulk still from producing the metal fine powder end as the parent material that forms metal film effectively, are preferably used to have most advanced and sophisticated needle-like or cylindrical metal fragment.
From producing the metal fine powder end as the parent material that forms metal film effectively, the size of metal fragment (length) should be in the scope of 0.05mm-10mm, and is better in the scope of 0.3mm-5mm, better in the scope of 0.5mm-3mm.Can use to have identical shaped and multiple metal fragment same size, can be used in combination metal fragment with difformity and different size.
Consider that magnet and metal fragment are easy to oxidation and corrosion, so preferably carry out the vibration and/or the stirring of magnet and metal fragment by the dry method mode.Can in atmosphere and ambient temperature, carry out the vibration and/or the stirring of magnet and metal fragment.The used process tank of the present invention does not need complicated structure, for example can be the process chamber in the tumbling mill.Tumbling mill can be rotary, oscillatory type or centrifugal well known device.In revolving situation, rotary speed should be in the scope of 20rpm-50rpm.In the situation of oscillatory type, vibration frequency should be in the scope of 50Hz-100Hz, and Oscillation Amplitude should be in the scope of 3mm-10mm.In centrifugal situation, rotation number should be in the scope of 70rpm-200rpm.
The amount of putting into the magnet of process tank and metal fragment should be in the scope of 20 volume %-90 volume % of process tank internal volume.If this amount is lower than 20 volume %, and is then very few and impracticable.If should amount surpass 90 volume %, then possibly can't form metal film effectively.The quantitative proportion of magnet and metal fragment should be (magnet/metal fragment) below 3 by volume.If this volume ratio surpasses 3, then may need the plenty of time, it is unpractical therefore surpassing 3 volume ratio.Processing time is depended on treating capacity, usually 1 hour-10 hours scope.
Adopt above-mentioned technology, be deposited on magnet surface from the metal fine powder end that metal fragment produces and form metal film.A kind of mechanico-chemical reaction of uniqueness can be thought in the metal fine powder end in the deposit phenomenon of magnet surface.The metal fine powder end is deposited on magnet surface securely, and the metal film of formation presents excellent corrosion resistance.The viewpoint of the corrosion resistance that collateral security is satisfied is set out, and the thickness of metal film should be equal to or greater than 0.01 μ m.The upper limit to thickness is not particularly limited.But the metal film that formation thickness surpasses 1 μ m needs the plenty of time, and therefore this technology is fit to form the metal film below the thick 1 μ m.
To heat-treating at the metal film that magnet surface forms by above-mentioned technology, can the enhancing magnet surface and metal film between adhesiveness.Can heat-treat in this stage, even but the heat treatment by the following formation metal oxide film that will illustrate also can obtain identical effect.Heat treatment temperature should be equal to or less than 500 ℃, because if temperature surpasses 500 ℃, then the magnetic property of magnet may descend, and perhaps metal film may melt.
Below explanation applies by as the hydrolysis of the metallic compound of the parent material of metal oxide film and the sol solution that polymerization reaction generates the metallic film surface that forms, and the sol solution that applies is heat-treated the operation that forms metal oxide film.
Metal oxide film can be the film that single metal oxide composition forms, or the composite membrane of multiple metal oxide film component formation.The metal oxide composition for example is to be selected from least a in aluminium oxide (Al), silica (Si), zirconia (Zr) and the titanium oxide (Ti).
Among the film that single metal oxide forms, because it is stable that the sol solution of formation silicon oxide film is compared with the sol solution that forms another kind of metal oxide film, so can form silicon oxide film (SiO in the lower temperature of situation than the film of another kind of metal oxide composition xFilm: 0<x≤2), so the advantage of this silicon oxide film is the influence that can reduce the magnet magnetic property.Zirconium oxide film (ZrO xFilm: 0<x≤2) advantage is that not only excellent corrosion resistance but also alkali resistance also are excellent.
If metal oxide film contains and (for example forms pellumina (Al on the aluminium film as the identical metal ingredient of the metal ingredient of the metal film of primary coating layers 2O xFilm: 0<x≤3)), then the advantage of this film is that adhesion between metal film and the metal oxide film is firm.
The example of the composite membrane that multiple metal oxide composition forms is Si-Al composite membrane (SiO xAl 2O yFilm: 0<x≤2 and 0<y≤3), Si-Zr composite membrane (SiO xZrO yFilm: 0<x≤2 and 0<y≤2), Si-Ti composite membrane (SiO xTiO yFilm: 0<x≤2 and 0<y≤2).The advantage that contains the composite membrane of silica composition is that sol solution is relatively stable, can form this film in low relatively temperature, so can reduce the influence to the magnet magnetic property.The advantage that contains the composite membrane of zirconia composition is the alkali resistance excellence.
If metal oxide film be contain with as the composite membrane of the identical metal ingredient of the metal ingredient of the metal film of primary coating layers (for example when the Si-Al complex oxide film is formed on the aluminium film, perhaps when the Si-Ti complex oxide film is formed on the titanium film), then the advantage of this complex oxide film is that the adhesion at interface between metal film and composite membrane is firm.
The used sol solution of sol-gel technology is the following solution of making, that is in organic solvent preparation as metallic compound, catalyst, stabilizer and the water in the source that forms metal oxide film, make colloid by hydrolysis and polymerization reaction, so that colloid is scattered in the solution.
The example of the metal oxide that uses as the source that forms metal oxide film, have metal alkoxide (can be have at least one alkoxyl by alkyl for example the displacement of methyl and ethyl or by the alkoxide of displacements such as phenyl), for example methoxide, ethylate, propylate, butylate; Metal carboxylate, for example oxalates, acetate, caprylate and stearate; Chelate compound, for example metal acetylacetonates; And inorganic salts, for example metal nitride and chloride.
Be used to form the situation that pellumina and zirconium compounds are used to form zirconium oxide film at aluminium compound, if consider the stability and the cost of sol solution, then preferably use alkoxide with the alkoxyl that contains 3-4 carbon atom, the for example propylate of aluminium and zirconium and butylate, carboxylate, for example metal acetate and metal octoates.Be used to form the situation of silicon oxide film at silicon compound, preferably use the alkoxide with the alkoxyl that contains 1-3 carbon atom, for example methoxide of silicon, ethylate and propylate.Be used to form the situation of oxidation titanium film at titanium compound, preferably use the alkoxide with the alkoxyl that contains 2-4 carbon atom, for example ethylate of titanium, propylate and butylate.
In order to form complex oxide film, can use the multiple metallic compound of its form of mixtures, can use separately or the metallizing thing uses for example metal composite alkoxide of metal composite compound in combination.For example, in order to form the Si-Al complex oxide film, can use the Si-Al complex chemical compound, for example have the Si-O-Al chemical bond and contain 1-4 carbon atom alkoxyl (some of them can with alkyl for example methyl and ethyl or with displacements such as phenyl) the Si-Al complex alkoxide.The object lesson of this compound has (H 3CO) 3-Si-O-Al-(OCH 3) and (H 5C 2O) 3-Si-O-Al-(OC 2H 2) 2
When using multiple metallic compound to form complex oxide film, the mixed proportion of every kind of metallic compound is not particularly limited, can determine according to component ratio at the complex oxide film of expectation.
For example, when preparing on aluminium (Al) film, to form the Si-Al complex oxide film, should mix and use Si compound and Al compound, perhaps mix and use Si compound and Si-Al complex chemical compound, so that the mol ratio (Al/Si+Al) of contained aluminium of Si-Al complex oxide film and silicon (Si) and aluminium (Al) mole total amount is equal to, or greater than 0.001.By according to these compounds of above-mentioned mixed in molar ratio, can improve the reactivity with the interface of aluminium film, in silicon oxide film, keep excellent performance (sol solution is stable, can form this film in quite low temperature) simultaneously.When heat-treating (following will the explanation) below 150 ℃, mol ratio should be below 0.5 after metallic film surface being applied sol solution.When carrying out this processing below 100 ℃, mol ratio should be below 0.2.This is because must improve heat treated temperature along with the increase of the mixed proportion of aluminium.
The ratio of the metallic compound of fusion should (be represented by the metal oxide ratios, for example press SiO in the situation of silicon compound in the scope of 0.1wt%-20wt% in sol solution 2Ratio is represented and is pressed SiO in the situation of silicon compound+aluminium compound 2+ Al 2O 3Ratio is represented).If this ratio is lower than 0.1wt%, then may need multiply periodic film to form operation, so that form film with satisfied thickness.If this ratio surpasses 20wt%, then may increase the viscosity of sol solution, thereby be difficult to form film.
May be used singly or in combin acids as catalyst, for example acetate, nitric acid and hydrochloric acid.The suitable addition of acid is determined by the hydrogen ion concentration in the sol solution of preparation, preferably adds acid, makes the pH value of sol solution in the scope of 2-5.If the pH value is less than 2 or surpass 5, then may when being applicable to the sol solution that forms film, preparation can not control hydrolysis react and polymerization reaction.
If desired, can be according to the chemical stability of used metallic compound, suitably to select to be used for the stabilizer of stable sol solution, but preferably can form compound with metal chelate, beta-diketon for example is as acetylacetone,2,4-pentanedione; And beta-keto esters, as ethyl acetoacetate.
When using beta-diketon, the amount of the stabilizer of mixing (stabilizer/metallic compound) in molar ratio should be equal to or less than 2.If mol ratio surpasses 2, then may hinder the hydrolysis and the polymerization reaction of preparation sol solution.
Can directly or indirectly add water to sol solution by chemical reaction, for example when using ethanol as solvent, the water that the esterification of employing and carboxylic acid produces perhaps adopts the steam in the atmosphere.Directly or indirectly when sol solution added water, the mol ratio of water/metallic compound should be equal to or less than 100.If mol ratio surpasses 100, then may influence the stability of sol solution.
Organic solvent is not particularly limited, can be any can uniform dissolution as the solvent of all metallic compounds, catalyst, stabilizer and the water of sol solution composition, so that the colloid that produces is dispersed in the solution.Operable representative examples of organic has, lower alcohol, for example ethanol; Hydro carbons ether alcohol, for example 1,2 ethylene glycol monoalky lether; The acetic acid esters of hydro carbons ether alcohol, for example 1,2 ethylene glycol monoalky lether acetic acid esters; The acetic acid esters of lower alcohol, for example ethyl acetate; And ketone, for example acetone.From the fail safe of processing procedure with become originally, should be used alone or in combination lower alcohol for example ethanol, isopropyl alcohol and butanols.
The viscosity of sol solution depends on the combination of contained various compositions in the sol solution, should be equal to or less than 20cP usually.If viscosity surpasses 20cP, then may be difficult to the adequate relief film forming, can produce cracking in the heat treatment process.
The time of preparation sol solution and the combination that temperature depends on contained various compositions in the sol solution.Generally, preparation time was 1 minute-72 hours scope, and preparation temperature is at 0 ℃-100 ℃.
The operable example that applies the method for sol solution to metallic film surface has dip coating technology, spraying coating process and spin coating proceeding.
After metallic film surface applies sol solution, the sol solution that applies is heat-treated.Required heating-up temperature can be the level that is enough to be evaporated to rare machine solvent.For example, when using ethanol as organic solvent, minimum temperature is 80 ℃ of the boiling points of ethanol.On the other hand, when adopting sintered magnet,, then may cause the reduction of magnet magnetic property, perhaps metal membrane-coating fusing if heating-up temperature surpasses 500 ℃.Therefore, the viewpoint of cracking takes place from prevent the cooling procedure after the heat treatment to greatest extent, heating-up temperature should be 80 ℃-500 ℃ scope, and is better 80 ℃-250 ℃ scope.When adopting bonded permanent magnet, the setting of heat treated temperature conditions must be considered the heat resisting temperature of used resin.For example, when adopting the bonded permanent magnet of being made by epoxy resin or polyamide, consider the thermal endurance of these resins, heating-up temperature should be 80 ℃-200 ℃ scope.Usually, heating time was at 1 minute-1 hour.
According to above-mentioned technology, can form basic is the metal oxide film of the excellent corrosion resistance of amorphous phase.For example, adopt the Si-Al complex oxide film, comprise a large amount of Si-O-Si chemical bonds and a large amount of Si-O-Al chemical bonds, comprise a large amount of Al-O-Al keys and a large amount of Si-O-Al keys in the situation of rich aluminium film in its structure of situation of Silicon-rich film.These two kinds of components in proportions are by the ratio decision of the metallic compound that mixes in the film.
According to above-mentioned technology, metal oxide contains the carbon (C) that derives from metallic compound and stabilizer.By comprising the metal oxide film that carbon is easy to make basic excellent corrosion resistance for amorphous phase, so carbon content should be in the scope of 50ppm-1000ppm (wt/wt).If carbon content is less than 50ppm, then film may ftracture.If carbon content surpasses 1000ppm, then the compactness extent of film may be not enough.
If its thickness of metal oxide film that is formed by above-mentioned technology is equal to or greater than 0.01 μ m, then has excellent corrosion resistance.To the upper limit of the film thickness that can form by above-mentioned technology without limits, but when magnet is assembled into parts that its temperature changes significantly for example when being used for the motor of automobile, from reducing the needs of the size of magnet own, with the collateral security durability, can be equal to or less than 10 μ m, preferably be equal to or less than 5 μ m, it is better to be equal to or less than 1 μ m.Certainly, if desired, apply sol solution and heat treatment subsequently can repeat repeatedly to metallic film surface.
Before forming metal oxide film on the metal film, can spray sclerosis (clashing into the technology of improving the surface to the surface) as operation in advance by grit, can make metal film level and smooth by spraying sclerosis, thereby help forming metal-oxide film with excellent anticorrosive.
The hardness that powder had that is used to spray sclerosis should be equal to or greater than the hardness of the metal film of formation.The example of this powder is that Mohs' hardness is at the spherical grit more than 3, for example steel ball and bead.If the average particle size particle size of powder is less than 30 μ m, the pushing force that then puts on metal film is less, so it is long to handle required time.On the other hand, if the average particle size particle size of powder surpasses 3000 μ m, then the smoothness on surface may be excessive, and the surface of making is irregular.Therefore, the average particle size particle size of powder is preferably in the scope of 30 μ m-3000 μ m, and is better at 40 μ m-2000 mu m ranges.
The air blast pressure that sprays in the sclerosis should be at 1.0kg/cm 2-5.0kg/cm 2Scope.If air blast pressure is less than 1.0kg/cm 2, the pushing force that then puts on metal film may be less, so it is long to handle required time.If blast surpasses 5.0kg/cm 2, the pushing force that then puts on metal film may be inhomogeneous, thereby cause the reduction of surface flatness.
The blasting time that sprays in the sclerosis should be 1 minute-1 hour scope.If blasting time is less than 1 minute, then possibly can't realize the uniform treatment on whole surface.If blasting time surpasses 1 hour, then may cause the reduction of surface flatness.
The contained rare earth element (R) of the Fe-B-R base permanent magnet that the present invention adopts is at least a element among Nd, Pr, Dy, Ho, Tb and the Sm preferably, in addition also has at least a element among La, Ce, Gd, Er, Eu, Tm, Yb, Lu and the Y.
Usually, one of these elements (R) are just enough, but in fact for the facility of obtaining, can use the mixture (mischmetal(l) and didymium) of two or more rare earth elements.
R content in the Fe-B-R base permanent magnet should be in the scope of 10at%-30at%.If R content is lower than 10at%, then brilliant structure is cube brilliant structure identical with α-Fe, so can not obtain high magnetic characteristics, particularly high-coercive force (iHc).On the other hand, if R content surpasses 30at%, the content of the non magnetic phase of then rich R increases, and residual magnetic flux density (Br) reduces, thereby can not make the permanent magnet with excellent properties.
Fe content is preferably in the scope of 65at%-80at%.If Fe content is less than 65at%, then residual magnetic flux density (Br) reduces.If Fe content surpasses 80at%, then can not obtain high-coercive force (iHc).
By improving temperature characterisitic and not influence the magnetic property of making magnet with Co part replacement of fe.But if the replacement amount of Co surpasses 20% of Fe, then magnetic property reduces, so this replacement amount is not expected.For high magnetic flux density is provided, the replacement amount of Co should be in the scope of 5at%-15at%, has improved residual magnetic flux density (Br) because compare with the situation of part replacement of fe not like this.
B content is preferably in the scope of 2at%-28at%.If B content is less than 2at%, then diamond structure is a principal phase, can not obtain high-coercive force (iHc).If B content surpasses 28at%, the content of the non magnetic phase of then rich B increases, and residual magnetic flux density (Br) reduces, thereby can not make the permanent magnet with excellent properties.
For the manufacturing that improves magnet with reduce cost, can contain at least a among the S of the P of 2.0wt% and 2.0wt% in the magnet, total amount is below the 2.0wt%.In addition, by using carbon (C) the replacing section B below the 30wt%, can improve the corrosion resistance of magnet.
And, add at least a among Al, Ti, V, Cr, Mn, Bi, Nb, Ta, Mo, W, Sb, Ge, Sn, Zr, Ni, Si, Zn, Hf and the Ga, help improving the squareness ratio of coercive force and demagnetization curve, and improve and make and reduce cost.In order to guarantee that maximum magnetic energy product (BH) max is equal to or greater than 20MGOe, wherein at least a addition should be in satisfying the scope that Br must be a 9kG condition at least.
Except R, Fe and B, the Fe-B-R base permanent magnet can contain unavoidable impurities in the magnet industry manufacturing.
The Fe-B-R base permanent magnet that the present invention adopts is characterised in that, comprises that principal phase (does not comprise the oxide phase) mutually with 1 the non magnetic of volume %-50 volume %, principal phase comprise have the tetragonal structure, average grain size is at the compound of 1 μ m-80 μ m.Magnet has iHc 〉=1kOe (79.6kA/m), Br>4kG (0.4T) and (BH) max 〉=10MGOe, and wherein the maximum of (BH) max reaches 25MGOe.
On metal oxide film of the present invention, can also form another film.By adopting this configuration, can strengthen the performance of metal oxide film, and provide further function for metal oxide film.
Embodiment
Disclosed as United States Patent (USP) 4770723, known ingot casting is pulverized, suppress successively then, sintering, heat treatment and Surface Machining, thereby manufacturing dimension is 23mm * 10mm * 6mm, consists of the sintered magnet (following will being called " magnet test sheet ") of 17Nd-1Pr-75Fe-7B.The magnet test sheet is carried out following experiment, wherein adopt the fluorescent X-ray thickness measurement equipment to measure the thickness of metal film, adopt the thickness of Electronic Speculum by the section survey metal oxide film of observation film.By the carbon content in the glow discharge mass spectrometry instrument measurement metal oxide film.In addition, adopt X-ray diffractometer to analyze the structure of metal oxide film.
Should notice that the present invention is not limited to Fe-B-R base sintered magnet, also can be applied to the Fe-B-R base bonded magnet.
Embodiment 1
150 magnet test sheets (apparent volume is that 0.5 liter, weight are 1.6kg) and diameter are that 0.8mm, length are the short column aluminium flake (apparent volume is that 20 liters, weight are 100kg) of 1mm, and the volume that drops into the oscillatory type tumbling mill is (its total amount is 40 volume % of process chamber inner volume) in 50 liters the process chamber.Under the condition of the amplitude of the vibration frequency of 60Hz and 1.8mm, carry out 5 hours dry process, thereby form the aluminium film then in magnet surface.The aluminium film that forms has the thickness of 0.05 μ m.
Prepare sol solution by following composition: aluminium compound, catalyst, stabilizer, organic solvent and water, form as shown in table 1ly, viscosity and pH are as shown in table 2.Adopt dip coating technology to apply sol solution to magnet, carry out heat treatment as shown in table 3 then and on the aluminium film, form pellumina with aluminium film according to the rate of pulling shown in the table 3.Film (the Al that forms 2O xFilm: 0<x≤3) has the thickness of 1 μ m.Carbon content in the film is 450ppm.Membrane structure is amorphous substantially.
Have pellumina on the magnet surface, accompany the aluminium film therebetween, make under the high temperature/super-humid conditions of relative humidity of its temperature that is in 80 ℃ and 90%, carry out 300 hours corrosion resistance accelerated test.Cosmetic variation after magnetic property before and after the test and the test is as shown in table 4.Be in for a long time under high temperature/super-humid conditions even found that magnet, it is bad that the magnetic property of magnet and outward appearance almost do not become yet, and enough satisfies required corrosion resistance.With modification acrylate based binder (product that the Hard loc G-55 that is made by DenkiKagaku Kogyo Kabushiki Kaisha numbers) magnet is bonded in castiron anchor clamps, it was kept 24 hours, carry out another test then, that is adopt the crush-cutting of Amsler tester to test, measure the shearing bond strength of magnet, obtain 331kgf/cm 2Excellent value.
Embodiment 2
By following composition prepare form, viscosity and pH value sol solution as shown in table 2: Si compound, catalyst, stabilizer, organic solvent and water, as shown in table 1.Adopt the magnet that has thick 0.05 μ m aluminium film on that dip coating technology is made in embodiment 1 according to the rate of pulling shown in the table 3 and its surface to apply sol solution, carry out heat treatment as shown in table 3 then and on the aluminium film, form silicon oxide film.The film that forms has the thickness (SiO of 0.8 μ m xFilm: 0<x≤2).Carbon in the film (C) content is 450ppm.Membrane structure is an amorphous.
Have silicon oxide film on the magnet surface of making by above-mentioned technology, accompany the aluminium film therebetween, under the condition identical, carry out the corrosion resistance accelerated test with embodiment 1.The result is as shown in table 4.Found that the magnet of making enough satisfies required corrosion resistance.Magnet is also carried out another test, that is with embodiment 1 the same terms under crush-cutting test, measure the shearing bond strength of magnet, thereby 274kgf/cm be provided 2Excellent value.
Embodiment 3
By following composition prepare form, viscosity and ph value sol solution as shown in table 2: Zr compound, catalyst, stabilizer, organic solvent and water, as shown in table 1.Adopt the magnet that has thick 0.05 μ m aluminium film on that dip coating technology is made in embodiment 1 according to the rate of pulling shown in the table 3 and its surface to apply sol solution, carry out heat treatment as shown in table 3 then and on the aluminium film, form zirconium oxide film.The film that forms has the thickness (ZrO of 1 μ m xFilm: 0<x≤2) carbon in thickness, the film (C) content is 450ppm.Membrane structure is an amorphous.
Have zirconium oxide film on the magnet surface of making by above-mentioned technology, accompany the aluminium film therebetween, under the condition identical, carry out the corrosion resistance accelerated test with embodiment 1.The result is as shown in table 4.Found that the magnet of making enough satisfies required corrosion resistance.
Embodiment 4
By following composition prepare form, viscosity and ph value sol solution as shown in table 2: Ti compound, catalyst, stabilizer, organic solvent and water, as shown in table 1.Adopt the magnet that has thick 0.05 μ m aluminium film on that dip coating technology is made in embodiment 1 according to the rate of pulling shown in the table 3 and its surface to apply sol solution, carry out heat treatment as shown in table 3 then and on the aluminium film, form oxidation titanium film.The film that forms has the thickness (TiO of 1 μ m xFilm: 0<x≤2) carbon in thickness, the film (C) content is 320ppm.Membrane structure is an amorphous.
Have oxidation titanium film on the magnet surface of making by above-mentioned technology, accompany the aluminium film therebetween, under the condition identical, carry out the corrosion resistance accelerated test with embodiment 1.The result is as shown in table 4.Found that the magnet of making enough satisfies required corrosion resistance.
Table 1
Metallic compound Catalyst Stabilizer Organic solvent
Embodiment 1 Aluminium butoxide Hydrochloric acid Do not have and add 2-methyl cellosolve
Embodiment 2 Dimethyldiethoxysilane Hydrochloric acid Do not have and add Ethanol
Embodiment 3 Zirconium caprylate Hydrochloric acid Do not have and add Isopropyl alcohol
Embodiment 4 Isopropyl titanate Nitric acid Do not have and add Ethanol
Table 2
The ratio of metallic compound (wt%) Mol ratio Viscosity (cP) pH
Catalyst/metallic compound Stabilizer/metallic compound Water/metallic compound
Embodiment 1 1 (annotating 1) 0.005 ?0 0 (annotating 5) 2.0 2.4
Embodiment 2 1 (annotating 2) 0.005 ?0 20 1.5 2.3
Embodiment 3 2 (annotating 3) 0.005 ?0 0 (annotating 5) 1.6 2.6
Embodiment 4 3 (annotating 4) 0.002 ?0 1 2.1 2.1
Annotate 1: press Al 2O 3
Annotate 2: press SiO 2
Annotate 3: press ZrO 2
Annotate 4: press TiO 2
Annotate 5: adopt the water vapour in the atmosphere
Table 3
The rate of pulling (cm per minute) Heat treatment Annotate
Embodiment 1 ?5 250 ℃ * 10 minutes Repeating five times lifts and heat treatment
Embodiment 2 ?5 150 ℃ * 10 minutes Repeating five times lifts and heat treatment
Embodiment 3 ?5 250 ℃ * 10 minutes Repeating five times lifts and heat treatment
Embodiment 4 ?5 50 ℃ * 10 minutes Repeating five times lifts and heat treatment
Table 4
Before the corrosion resistance test After the corrosion resistance test Test back outward appearance
Br (kG) iHc (kOe) (BH)max (MGOe) Br (KG) iHc (kOe) (BH)max (MGOe)
Embodiment 1 11.4 16.6 30.6 11.4 16.4 29.9 No change
Embodiment 2 11.4 16.6 30.6 11.4 16.3 29.8 No change
Embodiment 3 11.4 16.6 30.6 11.3 16.4 29.8 No change
Embodiment 4 11.5 16.5 30.6 11.3 16.3 29.7 No change
Comparative Examples 1 11.3 16.7 30.5 10.4 15.6 27.3 Get rusty in the part
Comparative Examples 2 11.4 16.6 30.6 10.0 15.2 26.5 The whole table street rust of living again
Comparative Examples 1
To the oil removing of magnet test sheet, in acid, flood and immerse 70 ℃ Treatment Solution, this solution comprises the zinc of 4.6g/l and the phosphate of 17.8g/l, thereby forms the phosphate layer of thick 1 μ m on magnet surface.Under the condition identical, the magnet of making is carried out the corrosion resistance accelerated test with embodiment 1.The result is as shown in table 4.The result makes the magnetic property decline of magnet and gets rusty.
Comparative Examples 2
Under the condition identical, the magnet test sheet is carried out the corrosion resistance accelerated test with embodiment 1.The result is as shown in table 4.The result makes the magnetic property decline of magnet and gets rusty.
Embodiment 5
Prepare sol solution by following composition: Si compound, Al compound, catalyst, stabilizer, organic solvent and water, its composition is as shown in table 5, and viscosity and ph value are as shown in table 6.Adopt the magnet surface that has thick 0.05 μ m aluminium film on that dip coating technology is made in embodiment 1 according to the rate of pulling shown in the table 7 and its surface to apply sol solution, carry out heat treatment as shown in table 7 then and on the aluminium film, form the Si-Al complex oxide film.Film (the SiO that forms xAl 2O yFilm: 0<x≤2 and 0<y≤3) thickness is 0.9 μ m, and carbon in the film (C) content is 290ppm.Membrane structure is an amorphous.
Have the Si-Al complex oxide film on the magnet surface of making by above-mentioned technology, accompany the aluminium film therebetween, under the condition identical, carry out the corrosion resistance accelerated test with embodiment 1.The result is as shown in table 8.Found that making magnet enough satisfies required corrosion resistance.This magnet is also carried out another test, that is with embodiment 1 the same terms under crush-cutting test, measure the shearing bond strength of magnet, thereby 323kgf/cm be provided 2Excellent value.
Table 5
Silicon compound Aluminium compound Catalyst Stabilizer Organic solvent
Embodiment 5 Dimethyldiethoxysilane S1-Al complex alkoxide (annotating 1) Hydrochloric acid Do not have and add Ethanol
Annotate 1:(H 5C 2O) 3SiOAl (OC 2H 5) 2The compound of representative
Table 6
Metallic compound ratio (wt%) Mol ratio Viscosity (cP) pH
?Al/Si+Al Catalyst/metallic compound Water/metallic compound
Embodiment 5 1 0.2 0.005 10 1.7 2.6
*Press SiO 2+ Al 2O 3
Table 7
The rate of pulling (cm per minute) Heat treatment Annotate
Embodiment 5 5 100 ℃ * 10 minutes Repeating five times lifts and heat treatment
Table 8
Before the corrosion resistance test After the corrosion resistance test Test back outward appearance
Br (kG) iHc (kOe) (BH)max (MGOe) Br (kG) iHc (kOe) (BH)max (MGOe)
Embodiment 5 11.4 16.6 ?30.6 11.4 16.3 ?29.8 No change
Embodiment 6
30 magnet test sheets (apparent volume is that 0.1 liter, weight are 0.32kg) and diameter are that 0.8mm, length are the short column Sn sheet (apparent volume is that 2 liters, weight are 11kg) of 1mm, drop into volume in the oscillatory type tumbling mill and are in 3.5 liters the process chamber (its total amount is 60 volume % of process chamber inner volume).Under the condition of the amplitude of the vibration frequency of 60Hz and 1.5mm, carry out 5 hours dry process, thereby form the Sn film then in magnet surface.The Sn film that forms has the thickness of 0.4 μ m.
Prepare sol solution by following composition: silicon (Si) compound, catalyst, stabilizer, organic solvent and water, form as shown in table 9ly, viscosity and pH are as shown in table 10.Adopt dip coating technology to apply sol solution to magnet, carry out heat treatment as shown in table 11 then and on the Sn film, form silicon oxide film with Sn film according to the rate of pulling shown in the table 11.Film (the SiO that forms xFilm: 0<x≤2) has the thickness of 0.3 μ m.Carbon content in the film is 350ppm.Membrane structure is an amorphous.
Have silicon oxide film on the magnet surface by above-mentioned technology manufacturing, accompany the Sn film therebetween, under the condition identical, carry out the corrosion resistance accelerated test with embodiment 1.The result is as shown in table 12.Found that the magnet of making enough satisfies required corrosion resistance.
Embodiment 7
150 magnet test sheets (apparent volume is that 0.5 liter, weight are 1.6kg) and diameter are that 1mm, length are the short column Zn sheet (apparent volume is that 20 liters, weight are 100kg) of 1mm, drop into volume in the oscillatory type tumbling mill and are in 50 liters the process chamber (its total amount is 40 volume % of process chamber inner volume).Under the condition of the amplitude of the vibration frequency of 60Hz and 1.8mm, carry out 5 hours dry process, thereby form the Zn film then in magnet surface.The Zn film that forms has the thickness of 0.2 μ m.
Prepare sol solution by following composition: silicon (Si) compound, catalyst, stabilizer, organic solvent and water, form as shown in table 9ly, viscosity and pH are as shown in table 10.Adopt dip coating technology to apply sol solution to magnet, carry out heat treatment as shown in table 11 then and on the Zn film, form silicon oxide film with Zn film according to the rate of pulling shown in the table 11.Film (the SiO that forms xFilm: 0<x≤2) has the thickness of 0.7 μ m.Carbon content in the film is 450ppm.Membrane structure is an amorphous.
Have silicon oxide film on the magnet surface by above-mentioned technology manufacturing, accompany the Zn film therebetween, under the condition identical, carry out the corrosion resistance accelerated test with embodiment 1.The result is as shown in table 12.Found that the magnet of making enough satisfies required corrosion resistance.
Embodiment 8
Prepare sol solution by following composition: zirconium compounds, catalyst, stabilizer, organic solvent and water, form as shown in table 9ly, viscosity and pH are as shown in table 10.Adopt that make in embodiment 7 according to the rate of pulling shown in the table 11 and magnet that have the Zn film of dip coating technology to apply sol solution, carry out heat treatment as shown in table 11 then and on the Zn film, form zirconium oxide film.Film (the ZrO that forms xFilm: 0<x≤2) has the thickness of 0.6 μ m.Carbon content in the film is 140ppm.Membrane structure is an amorphous.
Have zirconium oxide film on the magnet surface by above-mentioned technology manufacturing, accompany the Zn film therebetween, under the condition identical, carry out the corrosion resistance accelerated test with embodiment 1.The result is as shown in table 12.Found that the magnet of making enough satisfies required corrosion resistance.
Table 9
Metallic compound Catalyst Stabilizer Organic solvent
Embodiment 6 Tetramethoxy-silicane Nitric acid Do not have and add Ethanol
Embodiment 7 Dimethyldiethoxysilane Hydrochloric acid Do not have and add Ethanol
Embodiment 8 The butanols zirconium Acetate Ethyl acetoacetate Ethanol+isopropyl alcohol
Table 10
The ratio of metallic compound (wt%) Mol ratio Viscosity (cP) pH
Catalyst/metallic compound Stabilizer/metallic compound Water/metallic compound
Embodiment 6 10 (annotating 1) 0.001 0 1 1.8 3.2
Embodiment 7 1 (annotating 1) 0.005 0 20 1.5 2.3
Embodiment 8 5 (annotating 2) 2 1.5 1 1.7 3.8
Annotate 1: press SiO 2
Annotate 2: press ZrO 2
Table 11
The rate of pulling (cm per minute) Heat treatment Annotate
Embodiment 6 10 100 ℃ * 20 minutes
Embodiment 7 5 150 ℃ * 10 minutes Repeating five times lifts and heat treatment
Embodiment 8 5 350 ℃ * 20 minutes Repeating five times lifts and heat treatment
Table 12
Before the corrosion resistance test After the anti-examination of corrosion resistance Test back outward appearance
Br (kG) iHc (kOe) (BH)max (MGOe) Br (kG) iHc (kOe) (BH)max (MGOe)
Embodiment 6 11.4 16.4 30.4 11.3 16.3 29.8 No change
Embodiment 7 11.3 16.5 30.5 11.3 16.4 29.8 No change
Embodiment 8 11.4 16.5 30.6 11.3 16.4 29.8 No change

Claims (8)

1. the manufacturing process of a permanent magnet, have metal oxide film on the magnet surface, accompany metal film therebetween, comprise following operation, Fe-B-R base permanent magnet and metal fragment are put into process tank, and in process tank internal vibration and/or stirring, thereby form metal film on magnet surface, wherein R is a rare earth element; Described metallic film surface is applied sol solution, described sol solution is generated by hydrolysis and polymerization reaction by the metallic compound as the metal oxide film parent material, and described metal oxide film is made by at least a metal oxide composition that is selected from aluminium oxide, silica, zirconia and the titanium oxide; With the sol solution that applies is heat-treated, form metal oxide film, described heat treated temperature range is 80-500 ℃.
2. according to the technology of claim 1, wherein, use described metal fragment to form the metal film of making by at least a metal ingredient that is selected from aluminium, tin and the zinc.
3. according to the technology of claim 1, wherein, described metal fragment is needle-like or column, and length dimension is 0.05mm-10mm.
4. according to the technology of claim 1, wherein, described thickness of metal film is in the scope of 0.01 μ m-1 μ m.
5. according to the technology of claim 1, wherein, described sol solution is used to form metal oxide film, and described metal oxide film contains the metal ingredient identical with described metal film.
6. according to the technology of claim 1, wherein, the thickness of described metal oxide film is in the scope of 0.01 μ m-10 μ m.
7. according to the technology of claim 1, wherein, the content of described metal oxide film institute carbon containing is in the scope of 50ppm-1000ppm.
8. according to the technology of claim 1, wherein, described metal oxide film is formed by the metal oxide of amorphous phase.
CN99118336.3A 1998-08-31 1999-08-31 Process for mfg. Fe-B-R based permanent magnet with corrosion-resisting film Expired - Lifetime CN1131530C (en)

Applications Claiming Priority (11)

Application Number Priority Date Filing Date Title
JP262476/1998 1998-08-31
JP26247698 1998-08-31
JP279507/1998 1998-10-01
JP286628/1998 1998-10-08
JP28660298A JP3852224B2 (en) 1998-10-08 1998-10-08 Electrostatic micro relay
JP303731/1998 1998-10-26
JP30373198 1998-10-26
JP349915/1998 1998-12-09
JP34991598 1998-12-09
US09/382,588 US6444328B1 (en) 1998-08-31 1999-08-25 FE-B-R based permanent magnet having corrosion-resistant film, and process for producing the same
JP27950799A JP2001101981A (en) 1999-09-30 1999-09-30 Color cathode-ray tube and electron gun

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