JP4628869B2 - Carbon mold production method, permanent magnet particle production method, granulated powder production method for bond permanent magnet, and bond permanent magnet production method - Google Patents

Description

  The present invention relates to a permanent magnet manufacturing method for finally manufacturing a bonded magnet-type permanent magnet, and more particularly to a carbon mold manufacturing method, a permanent magnet particle manufacturing method, and a bonded permanent magnet granulated powder manufacturing method.

The types of permanent magnets are roughly classified into cast magnets, sintered magnets, and bonded magnets.
A typical cast magnet is an Alnico (Al-Ni-Co) magnet, which has a high magnetic flux density and good temperature characteristics, but is very hard, difficult to process, and expensive. It is used for special purposes such as.
Sintered magnets are typified by ferrite magnets, which are manufactured by sintering magnetic powder containing iron oxide as a main component into a predetermined shape. Although the residual magnetic flux density is somewhat low, it is inexpensive and has high coercive force. Used in a wide range of fields.
Bonded magnets are formed by mixing magnetic powder, epoxy resin, phenolic resin, polyamide synthetic resin (trade name, nylon), rubber, additives, etc., and are flexible and highly flexible. Since the residual magnetic flux density and the coercive force can be increased by including powder, it is widely used in many fields including small motors.
For example, in Patent Document 1, the raw material powder, which is a resin-coated magnetic powder, has a substantially spherical shape, and preferably has a particle size distribution of a normal distribution to improve the fluidity of the powder. It is disclosed to increase the packing density of the raw material powder when it is filled.
In Patent Document 2, an Nd-Fe-B permanent magnet alloy is melted to obtain a powder by a spray method, and then this powder is subjected to hydrogen storage and collapse treatment, and then hydrogen storage and collapse processing. A method for producing a permanent magnet alloy powder for further finely pulverizing the powder is disclosed.
Patent Document 3 proposes a method for producing nanoporous carbon as carbon having nano-sized pores.
As described above, the powder (particles) used in the conventional bonded magnet is produced with magnetic particles having a particle size of micron order by a metal dissolution method or a direct reduction method. Also, permanent magnets with a new concept of exchange spring magnets have been produced by granulating and molding these micron-order magnetic particles. Further, for nanoporous carbon, application of catalysts, hydrogen storage materials, membranes, etc. is considered.
Japanese Patent Laid-Open No. 7-74012 Japanese Patent Laid-Open No. 2002-60806 JP 2004-161590 A

In the method for producing a permanent magnet disclosed in Patent Documents 1 and 2, magnetic particles having a particle size on the order of microns are produced, but the compression-molded bond magnet has a characteristic of 239 kJ / m ³ or more, an injection-molded bond magnet. As a characteristic, there was a problem that an energy product of 160 kJ / m ³ or more could not be obtained, and there was a limit in improving magnetic characteristics.
Further, in Patent Document 3, a method for producing nanoporous carbon has been proposed as carbon having nano-sized pores. However, since the production method is different, as a template for producing metal particles, There was a disadvantage that could not be used.
The present invention has been made in view of such problems, and an object of the present invention is to provide a method capable of producing permanent magnet particles using a carbon mold and producing a high-performance permanent magnet using permanent magnet particles. To do.

In order to solve the above problem, the present invention is as follows.
The invention according to claim 1 relates to a carbon template preparation method, wherein at least water, hydrazine, ammonia, and tetraethyl orthosilicate are added to a solution composed of polyoxyethylene (n = 15) cetyl ether and cyclohexane . Nano-sized pores are formed by a step of forming silica having a particle size of 1000 nanometers, a step of firing in an argon atmosphere, and a step of immersing the obtained fired product in sodium hydroxide to dissolve the silica. We are going to make a carbon mold with
The invention according to claim 2 relates to a method for producing permanent magnet particles, a step of pouring a metal salt aqueous solution as a magnet raw material into the carbon template produced by the carbon template production method according to claim 1, and a calcium reduction treatment thereof. This step is characterized in that 1 to 1000 nanometer permanent magnet particles are produced.
A third aspect of the present invention is the permanent magnet particle manufacturing method according to the second aspect, wherein the metal in the aqueous metal salt solution is at least one of R-Fe-B, R-Fe-N, and R-Co-Fe. It is made of one alloy, and R is characterized by containing at least one rare earth metal element.
Invention of Claim 4 is related with the granulated powder preparation method for bond permanent magnets, The resin mixing step which mixes the permanent magnet particle produced by the permanent magnet particle preparation method of Claim 2 or 3, and resin, A granulated powder for bonded permanent magnets having nano-sized permanent magnet particles is produced by a granulating step of granulating the mixture obtained in the resin mixing step.
The invention according to claim 5 is characterized in that, in the granulated powder manufacturing method for bond permanent magnet according to claim 4, at least one of an epoxy resin, a phenol resin and a polyamide synthetic resin is added in the resin mixing step. Yes.
According to a sixth aspect of the present invention, in the granulated powder for bonded permanent magnet according to the fourth or fifth aspect, in the granulating step, the mixture of the permanent magnet particles and the resin solution is granulated by a spray drying method. It is characterized by that.
Invention of Claim 7 is related with the manufacturing method of a bond permanent magnet, and combines the granulated powder obtained by the granulated powder preparation method for bond permanent magnets of any one of Claims 4-6 with resin. Thus, a bonded permanent magnet having nano-sized permanent magnet particles is manufactured by molding into a predetermined shape.
The invention described in claim 8 is the method for manufacturing a bonded permanent magnet according to claim 7, wherein the molding step uses a compression molding method or an injection molding method.

According to the invention of claim 1, at least water, hydrazine, ammonia, and tetraethyl orthosilicate are added to a solution composed of polyoxyethylene (n = 15) cetyl ether and cyclohexane to obtain a particle size of 1 to 1000 nanometers. A carbon mold having nano-sized pores can be produced by forming a silica having a porous structure and then firing the resultant in an argon atmosphere and immersing the obtained fired product in sodium hydroxide to dissolve the silica. Since this template can be used, permanent magnet particles of 1 to 1000 nanometers can be easily produced.
According to the invention described in claim 2, permanent magnet particles of 1 to 1000 nanometers can be produced by pouring a metal salt aqueous solution, which is a magnet raw material, into the produced carbon mold and performing a calcium reduction treatment.
Further, since permanent particle growth is not observed in high-temperature heat treatment such as calcium reduction treatment as compared with conventional permanent magnet particles, permanent magnet particles having a high energy product can be produced.
According to the invention described in claim 3, at least one alloy of R—Fe—B, R—Fe—N, and R—Co—Fe is used, and said R contains at least one rare earth metal element. By producing permanent magnet particles, nano-order permanent magnet particles having respective characteristics can be produced.
According to the fourth aspect of the present invention, a granulated powder for bonded permanent magnets having nano-sized permanent magnet particles and having a uniform size is obtained by the granulating step of granulating the mixture obtained in the resin mixing step. be able to.
According to the invention described in claim 5, the permanent magnet particles thus produced are mixed with particles and a resin to which at least one of an epoxy resin, a phenol resin and a polyamide synthetic resin is added. Can be produced.
According to the invention of claim 6, it is possible to easily obtain a granulated powder for bonded permanent magnets having a small size and a uniform size by granulating a mixture of permanent magnet particles and a resin solution by a spray drying method. Since permanent magnet particles can be filled with high density, a permanent magnet having a high energy product can be obtained.
According to the seventh aspect of the present invention, by bonding the obtained granulated powder into a predetermined shape, a bonded permanent magnet having a shape corresponding to the application can be produced.
According to invention of Claim 8, the bond permanent magnet of the shape according to a use can be easily manufactured by using the compression molding method or the injection molding method.

  Hereinafter, specific examples of the method of the present invention will be described with reference to the drawings.

A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a flowchart showing a method for producing permanent magnet particles according to the present invention.
In FIG. 1, in Step 1, 5 cc of water, hydrazine, NH ₃ , and tetraethyl orthosilicate (Si (OC ₂ H ₅ ) ₄ , abbreviated TEOS) are added to 50 cc of a C-15 / cyclohexane solution. Here, C-15 is polyoxine ethylene (n = 15) cetyl ether. Thus, by adding water, hydrazine, NH ₃ , and TEOS, spherical silica having a particle diameter of 1 to 1000 nanometers is formed, and a carbon template material is obtained (step 2).
Next, in Step 3, argon (Ar) firing is performed at 850 ° C. for 5 hours, thereby solidifying the carbon template containing spherical silica having a particle diameter of 1 to 1000 nanometers.
In step 4, the spherical silica is etched with a 2 mol / liter NaOH aqueous solution for about 3 hours, so that the portion where the spherical silica is present becomes a cavity, and a carbon template is produced.
Thereafter, a container containing a carbon mold in a metal salt aqueous solution, which is a magnet raw material, is placed in a vacuum chamber. The vacuum mold is degassed by evacuating the vacuum chamber, and impregnated with the metal salt aqueous solution. Subsequently, 0.5 mol / liter of Ca (NO ₃ ) ₂ aqueous solution is added in excess (as much as possible). The metal is made of at least one alloy of R—Fe—B, R—Fe—N, and R—Co—Fe, and R contains at least one rare earth metal element. Since the air in the carbon mold is expelled by vacuum impregnation and the vacuum state is set, the magnet raw material can enter the pores having a particle diameter of 1 to 1000 nanometers in the carbon mold.
In step 5, an aqueous Ca (NO ₃ ) ₂ solution penetrates into the carbon mold and is reduced by heating in Ar (argon) at 850 ° C. for 8 hours. A Ca (NO ₃ ) ₂ aqueous solution is impregnated in the same manner as the metal salt.
Thereafter, the carbon mold is mechanically pulverized by using a mill to remove the carbon mold, whereby permanent magnet particles having a particle diameter of 1 to 1000 nanometers in the pores are taken out.
In step 6, permanent magnet particles are produced as described above.

FIG. 2 and subsequent figures are diagrams illustrating the method of the present invention, and FIG. 2 is a diagram in the middle of producing a carbon template by inserting spherical silica. In FIG. 2, water, hydrazine, NH ₃ , and TEOS are added to a C-15 / cyclohexane solution to form spherical silica 1 having a particle diameter of 1 to 1000 nanometers, and carbon firing 2 by performing Ar firing. Solidifies. Then, when this is immersed in NaOH aqueous solution and the spherical silica 1 is etched, the part of the spherical silica 1 will be removed and the carbon template 3 provided with many holes 3a with a particle diameter of 1-1000 nanometers will be obtained later. FIG. 3 is a view showing the carbon template 3 having a large number of holes 3a obtained in this manner.
Next, when the carbon template 3 is vacuum-impregnated with an aqueous solution of SmCoFe metal salt (aqueous solution of samarium chloride, cobalt chloride, and iron chloride) that is a magnet raw material, SmCoFe metal enters. FIG. 4 is a view showing a state in which the SmCoFe metal has entered the voids 3a of the carbon template 3 in this way.
Thereafter, by adding a Ca (NO ₃ ) ₂ aqueous solution and performing reduction diffusion treatment, the carbon template 3 is removed, and the permanent magnet particles 4 are obtained.
FIG. 5 is a diagram showing a large number of permanent magnet particles 4 having a particle diameter of 1 to 1000 nanometers thus obtained.

Table 1 is a figure which shows the size which can produce a permanent magnet particle.

In Table 1, horizontal numbers 0.5, 1, 10, 100, 1000, and 1200 in the upper column indicate the size of the permanent magnet particles in the unit of nm, and ○ and X in the lower column indicate the production of the permanent magnet particles. Possible (◯) and impossible (×) are shown.
As can be seen from Table 1, according to the method of the present invention, it is difficult to produce permanent magnet particles smaller than 1 nm, but particles having a size of 1 nm or more can be easily formed to particles having a size of 1000 nm or 1200 nm. It is that.

In Example 2 of the present invention, a carbon template was prepared in the same manner as in Example 1, and an aqueous metal salt solution of Sm and Co (samarium chloride aqueous solution 0.12 mol / liter, cobalt chloride aqueous solution 0.12 mol / liter). And, if necessary, impregnated with an aqueous solution of Fe metal salt (iron chloride aqueous solution 0.6 mol / liter), heat-treated at 850 ° C. for 5 hours, and performing Ca reduction diffusion treatment to produce permanent magnet particles, Thereafter, 2% by weight of butanone and epoxy resin are mixed with the permanent magnet particles (for example, 10 g of permanent magnet particles, 22.5 ml of butanone, 3.6 g of epoxy resin (density 0.379 g / ml)), and are placed in a spray dryer. Spraying was performed at ² kg / cm ² and 60 ° C., and dried in an Ar gas stream to prepare granulated powder.
The granulated powder was bonded with an epoxy resin, a nylon resin, or an acrylic resin, and a bonded magnet was produced by compression molding.
Then, the relationship between the size (nm) of permanent magnet particles and the energy product (Kj / m ³ ) was examined.
Table 2 is a diagram showing the magnetic characteristics of the bonded magnet according to the particle size of the permanent magnet particles.

In Table 2, the numbers 1, 10, 100, 1000, and 1200 in the horizontal direction in the upper column indicate the size of the permanent magnet particles in the unit of nm, and the numbers in the lower column indicate the energy product (Kj / m ³ ). Yes.
It can be seen from Table 2 that if the size of the permanent magnet particles is up to 1000 nm, a maximum energy product of 160 kJ / m ³ or more can be obtained. This means that only a magnet with a lower than 160 kJ / m ³ can be obtained.
Accordingly, it can be seen that, in order to obtain a magnet having a maximum energy product of 160 kJ / m ³ or more, it is important to form permanent magnet particles of 1000 nm or less according to the present invention. As described above, the injection-molded bonded magnet according to the prior art could not obtain a magnet having an energy product of 160 kJ / m ³ or more. However, according to the method of the present invention, if it is formed into permanent magnet particles of 1000 nm or less, the maximum A magnet having an energy product of 160 kJ / m ³ or more can be obtained.
Table 1 and Table 2 are summarized as follows. According to the method of the present invention, permanent magnet particles having a size of 1 nm or more can be produced from Table 1, and from Table 2, the size of the permanent magnet particles is 1000 nm or less. Then, it has been found that a product having a maximum energy product of 160 kJ / m ³ or more can be obtained. Therefore, in the step of forming silica, it is preferable to form silica having a particle diameter of 1 nm to 1000 nm.

Next, a method for finally producing a permanent magnet using the permanent magnet particles produced by the method of the present invention shown in FIG. 1 will be described with reference to FIG.
In FIG. 6, first, Step 11 is a permanent magnet particle production process, which is the flow of FIG.
In step 12, the permanent magnet particles are mixed with a resin to which at least one of an epoxy resin, a phenol resin, and a polyamide synthetic resin is added. Thus, the bonded magnet excellent in moldability can be produced by mixing at least one of each solution of an epoxy resin, a phenol resin, and a polyamide-based synthetic resin.
In step 13, a mixture obtained by mixing permanent magnet particles in a resin solution is granulated. Granulation can be performed by spray drying a mixture of permanent magnet particles and a resin solution.
By such granulation, permanent magnet particles can be filled with high density in the mold, so that a permanent magnet having a high energy product can be produced.

FIG. 7 is a diagram showing one granulated powder that has been granulated into small grains with uniform grains by the spray drying method.
In the figure, 5 is granulated powder, and it can be seen that the resin of the granulated powder 5 contains a large number of permanent magnet particles 4 produced by the above method.
In step 14, the granulated powder 5 (FIG. 7) granulated in this manner is put into a mold 6 (FIG. 8 a) having a predetermined shape and is pressurized with a pressure P, so that a permanent magnet having a desired shape is obtained. Is manufactured. For the molding, an existing compression molding method or injection molding method may be used.

FIGS. 8A and 8B are conceptual diagrams showing the molding process of Step 14, wherein FIG. 8A shows a molding process according to the present invention, and FIG. 8B shows a molding process according to a conventional method. The mold 6 itself is the same, but the magnetic particles put in it are (a) a resin containing a large number of permanent magnet particles 4 having a particle diameter of 1 to 1000 nanometers according to the present invention, and by spray drying. Since it is the granulated powder 5 (FIG. 7) granulated into small grains with uniform grains, the granulated powder 5 can be uniformly stored in the mold 6 with no high gap.
In this way, a high-performance bonded magnet having nano-order permanent magnet particles can be easily manufactured.
On the other hand, since magnetic particles 5 'having different sizes are stored in the mold 6 because they are not granulated in (b), a lot of gaps are formed, the filling rate is lowered, and the maximum energy product is increased. Since it becomes small, it is difficult to obtain a high-performance bonded magnet.

  Since the present invention can improve the performance of a permanent magnet by producing a bonded magnet from permanent magnet particles having a nano-order particle diameter, the present invention can be applied to the use of improving the performance of a servo motor.

It is a flowchart which shows the manufacturing method of a permanent magnet particle. In order to implement the method of this invention, it is a figure in the middle of producing a carbon template by inserting spherical silica. It is a figure which shows the carbon template which has many void | holes produced by this invention. It is a figure which shows the state which the metal entered in the void | hole of the carbon casting_mold | template. It is a figure which shows the permanent magnet particle of the particle diameter of 1-1000 nanoparticles produced by this invention. It is a flowchart explaining the method of manufacturing a permanent magnet using the permanent magnet particle produced by the method of this invention. It is a figure which shows 1 grain of the granulated powder granulated by the granulation process at the small granule. It is a conceptual diagram which shows the shaping | molding process of step 14, (a) is a shaping | molding process which concerns on this invention, (b) is a shaping | molding process which concerns on a conventional method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Spherical silica 2 Carbon mold 3 in preparation 3 Carbon mold 3a Hole in carbon mold 4 Permanent magnet particle 5 Granulated powder 6 Mold P Pressure

Claims (8)

Adding at least water, hydrazine, ammonia, and tetraethyl orthosilicate to a solution composed of polyoxyethylene (n = 15) cetyl ether and cyclohexane to form silica having a particle size of 1 to 1000 nanometers; A carbon mold characterized in that a carbon mold having nano-sized pores is produced by performing a firing in an argon atmosphere and a step of immersing the obtained fired product in sodium hydroxide to dissolve the silica. Manufacturing method.   A permanent magnet particle of 1 to 1000 nanometers is produced by a step of pouring a metal salt aqueous solution, which is a magnet raw material, into the carbon template produced by the carbon template production method according to claim 1 and a step of reducing the calcium salt. A method for producing permanent magnet particles.   The metal of the metal salt aqueous solution is composed of at least one alloy of R—Fe—B, R—Fe—N, and R—Co—Fe, and R contains at least one rare earth metal element. The method for producing permanent magnet particles according to claim 2.   A resin-mixing step of mixing the permanent magnet particles produced by the permanent magnet particle production method according to claim 2 or 3 and a resin, and a granulating step of granulating the mixture obtained in the resin mixing step, A method for producing a granulated powder for bonded permanent magnets, comprising producing a granulated powder for bonded permanent magnets having permanent magnet particles.   5. The method for producing a granulated powder for bonded permanent magnets according to claim 4, wherein at least one of an epoxy resin, a phenol resin and a polyamide-based synthetic resin is added in the resin mixing step.   6. The granulated powder production method for bond permanent magnet according to claim 4, wherein in the granulating step, the mixture of the permanent magnet particles and the resin solution is granulated by a spray drying method. Nanosized permanent magnet particles obtained by bonding the granulated powder obtained by the method for producing a granulated powder for bonded permanent magnet according to any one of claims 4 to 6 with a resin and forming the resultant into a predetermined shape. A method for producing a bond permanent magnet, comprising producing a bond permanent magnet having a magnetic field.
Manufacturing method.   The method for manufacturing a bonded permanent magnet according to claim 7, wherein a compression molding method or an injection molding method is used in the molding step.

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