JPH0231401A - Rare-earth magnet alloy powder, manufacture thereof and macromolecular composite type rate-earth magnet using this alloy powder - Google Patents

Abstract

PURPOSE:To obtain the powder, to be used for rare-earth plastic magnet, having high magnetic field orientational property, high coercive force and excellent oxidation- resisting property by a method wherein an organic electroplated layer is provided on the surface of the alloy powder, having an intermetallic compound consisting of a rare-earth element containing Y, a transition metal and B, as the main phase. CONSTITUTION:An organic electroplated layer is provided on the surface of R-T-B alloy powder, having an R2T14B (R is the rare-earth element containing Y, and T is a transition metal) intermitallic compound, as the main phase. Said organic electroplated layer contains a metal layer containing at least a kind of R-T and R-T-B, and also at least a kind of Ni, Al, Cu, Zn, Co, Fe, Mo and Ti. After R-T and R-T-B alloy, having R-metal or R-rich phase as the main phase, has been organically electroplated on the R-T-B powder having Nd2Fe14B phase as the main phase, a metal or an alloy having resistance to oxidation such as Ni, Cu, Al and the like is plated in addition to the above-mentioned plating. As a result, the powder for plastic magnet having excellent magnet characteristics and corrosion resistance can be manufactured.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is directed to R, T14B represented by Nd*Fe+<B.
The present invention relates to an RTB permanent magnet alloy powder containing an intermetallic compound as a main phase, and particularly relates to the powder, its manufacturing method, and a polymer composite rare earth magnet using the powder.

<Prior Art> In recent years, Nd-Fe-B magnets having higher magnetic properties than Sm-Co magnets have been developed as high-performance magnets, and their applications are expanding. This Nd-Fe-B
Broadly speaking, there are two types of permanent magnets: sintered magnets and plastic magnets (also called plastic magnets).

Among these, the manufacturing method and composition of sintered magnets have almost been established, and products with high magnetic properties are manufactured on industrial lines.
provided to the user.

However, in the field of plastics, the magnetic properties are currently poor and the manufacturing process has not yet been established. Therefore, a plastic product with high magnetic properties that satisfies users has not been provided.

Currently, Nd-Fe-B alloy powders for plastic mags include liquid quenched alloy powder obtained by quenching molten alloy (referred to as first alloy powder), and powder obtained by hot processing this liquid quenched alloy powder (second alloy powder). Three types have been proposed: a powder obtained by crushing a sintered body or an ingot (referred to as a third alloy powder);

However, although the first alloy powder has a high Hc, since the powder is isotropic, magnetic field orientation is not possible, and Sm-
It is not possible to produce 1-Ramag with a higher (B H) iax than the Co-based powder, and the second one was developed to further improve this drawback and give the powder anisotropy.
This is the second alloy powder obtained by hot working the liquid quenched alloy powder. This method involves hot working an isotropic liquid quenched alloy powder to give it a certain type of texture.
The aim is to make the shape anisotropic. Although this method produces a certain degree of magnetic field orientation effect and improves Br, the effect is small and further causes a decrease in Hc. Moreover,
The third method, which is industrially undesirable due to its complicated process and large cost increase, is the method of using pulverized powder of sintered bodies or ingots, which replaces the conventional manufacturing method of Sm-Co plastic mag with Nd-Fe- This is applied directly to B.

However, although it is possible to improve Br by magnetic field orientation with this method, Nd-Fe-B powder causes a significant deterioration of Hc by pulverization, so it cannot be applied as a powder for plastic mags.The reason for this is the The decrease in Hc is due to the process-altered layer on the powder surface, and the main cause is that the crushed powder is necessarily wrapped in a neodymium-rich phase, which is essential for the generation of coercive force of Hd-Fe-B. This is because there is no guarantee that there will be any.

In other words, in the present magnet, when the magnetic phase Nd1Fe+*B phase is wrapped in the Ndrich phase, this Ndri
It is thought that a high coercive force is generated because the movement of the domain wall is trapped in the ch phase. Therefore, when the magnetic phase is exposed on the powder surface, the domain wall is freely reversed from this location, so
Coercive force deteriorates significantly. Moreover, this Nd2Fe+
The iB phase alone cannot function as a magnet.

Moreover, since the present magnet powder mainly contains rare earth elements and Fe, which are extremely active in the atmosphere, it is easily oxidized.

In addition, especially during injection molding, the temperature is raised to around 200°C to lower the viscosity of the polymer and improve moldability, but this also has the disadvantage that magnetic properties deteriorate due to the effects of high-temperature oxidation. was.

Furthermore, even after molding, there are parts of the plastic mag surface where the powder surface is exposed, so oxidation progresses from these parts even during use, so by applying various chemical treatments to the powder surface in advance, Efforts have been made to make the plastic oxidation resistant, but this is still far from sufficient, and the reality is that a resin coating is applied to the surface of the molded plastic for oxidation resistance, increasing costs. .

[Problem to be solved by the invention] That is, from the points mentioned above, both Nd and Fe-
It was not suitable as a B-series plastic powder.

In addition, the composition of this alloy contains elements that are easily oxidized in the atmosphere, such as Nd and Fe, and the alloy, alloy powder, and sintered body will oxidize and rust due to moisture in the atmosphere. .

Therefore, it is difficult to handle these alloy powders, and the characteristics deteriorate due to oxidation of the magnet powder during processes such as heat hardening when manufacturing bonded magnets. Furthermore, even after being made into a bonded magnet, since the powder is exposed on the surface, oxidation progresses from there, not only degrading the magnetic properties but also causing contamination of surrounding parts and extreme In some cases, the bonded magnet was even destroyed due to the progress of oxidation.

As a countermeasure to this problem, powders are treated with Ti coupling or silane coupling agents, but the reality is that these treatments are almost completely ineffective. Another method is to coat the surface of the bonded magnet with an oxidation-resistant resin after creating it, but it is not possible to completely coat the complex shape or elongated cylindrical shape formed by injection molding etc. In some cases, this method is not suitable as a countermeasure.

The technical problems of the present invention are as follows: (1) N d 2 F 614B phase is N d ric
By producing a powder surrounded by an h layer, the effect of magnetic field orientation is increased and a powder with high Br and high +Hc is produced.

(2) Furthermore, oxidation resistance is imparted by forming an organic electrolytic plating layer of Ni, Cu, etc. on the surface of this powder.

By achieving the above two points using the a-containing electrolytic plating method,
It is an object of the present invention to provide a rare earth plastic magnet powder having high magnetic field orientation, high coercive force, and excellent oxidation resistance, and a method for producing the same at low cost.

Another technical problem of the present invention is to coat these powders for bonded magnets with metals or alloys that have excellent corrosion resistance by electrolytic plating. The purpose of the present invention is to provide a powder and a method for producing the same.

Yet another technical problem of the present invention is to solve these R
An object of the present invention is to provide a polymer composite rare earth magnet using -T-B alloy powder.

Means for Solving the Problem] According to the present invention. Rt T14B (R represents a rare earth element containing Y, T represents a transition metal) Characterized by having an organic electrolytic plating layer on the surface of the R-T-B alloy powder whose main phase is an intermetallic compound. A rare earth magnet alloy powder is obtained.

According to the present invention, in the rare earth magnet alloy powder, the organic electrolytic plating layer is. R, R-T. A rare earth magnet alloy powder containing at least one type of R-T-B is obtained.

Further, according to the present invention, in the rare earth magnet alloy powder, the organic electrolytic plating layer is made of Ni or AJ.

At least one of Cu, Zn, Co, Fe, Mo, and Ti
A rare earth magnet alloy powder is obtained which is characterized by containing a metal layer (including an alloy layer) consisting of seeds.

According to the invention. R, T14B (However, R represents a rare earth element containing Y, and T represents a transition metal.) On the surface of R-T-B alloy powder whose main phase is an intermetallic compound. R, R-T.
A method for producing rare earth magnet alloy powder is obtained, which includes a first plating step of electrodepositing a first organic electrolytic plating layer made of at least one type of R-T-B.

According to the present invention, in the method for producing rare earth magnet alloy powder, Ni, A
J! , Cu, Zn, Co, Fe.

A method for producing a rare earth magnet alloy powder is provided, which comprises a second plating step of electrodepositing a second organic electrolytic plating layer of a metal (including alloy) made of at least one of Mo and Ti. It will be done.

Here, in the method for producing rare earth magnet alloy powder of the present invention, as a step after the second plating step, 400 to 1000
It is desirable to include a heat treatment step of heat treatment at °C.

According to the present invention, a polymer composite rare earth magnet is obtained by molding the rare earth magnet alloy powder using a polymer resin.

Here, in the present invention, molding using a polymer resin means mixing a polymer into raw material powder and obtaining a molded product by compression molding, extrusion molding, or injection molding, or molding by compression molding from raw material powder. It involves applying or impregnating the body with a polymeric resin.

As mentioned above, the Nd-Fe-B type 1 Ramag powder utilizes the high coercive force characteristics of the liquid rapidly solidified alloy powder, and the high magnetic field orientation of the crushed powder of the Nd-Fe-B sintered body or ingot. It was proposed that
In either case, it is not possible to take advantage of both the characteristics of the sintered Nd-Fe/B magnet, which has high Br and high coercive force due to its magnetic field orientation.

In addition, the oxidation resistance, which is a very serious problem in terms of implementation, has not been solved.

As a result of various studies, the present inventors have discovered that Nd can be plated on the Nd2T, B phase by using an Im-containing electrolytic plating method, leading to the present invention.

Furthermore, the inventors discovered that various metals or alloys can be plated on R-T-B alloy powder by using organic electrolytic plating using an organic solvent, leading to the present invention.

In other words. Since the R-T-B magnet alloy is an alloy that is extremely easily oxidized, it has been impossible to plate it by plating using a normal aqueous solution because the alloy powder will oxidize during the plating process. Furthermore, we focused on the fact that Nd metal does not oxidize in organic solvents, and by applying oxidation-resistant plating (Ni, Cu, etc.) on the Nd metal surface by organic electrolytic plating, we created the magnet powder with excellent oxidation resistance of the present invention. It is something that could have been invented.

That is, according to the present invention, Nd metal or mainly N d is added to the RT-8 alloy powder whose main phase is Nd1Fe+<B phase.
RT. whose main phase is rich phase. By plating RT-B alloy by organic electrolytic plating method, Nd2Fe1
It is possible to obtain a powder that takes advantage of both the characteristics of high Br due to the high uniaxial magnetic anisotropy of the 4B phase and high coercive force obtained by wrapping the Nd2Fet4B phase in a rich phase.

Furthermore, in this powder state, the powder surface is Rrich.
Although this powder has poor oxidation resistance due to its oxidation resistance, it is possible to impart oxidation resistance to this powder by further plating with Ni, Cu, etc. using an organic electrolytic plating method. Furthermore, these powders are heated to 400 to 1000℃.
By heat-treating at a temperature of , it is possible to further improve the coercive force, and it is also possible to improve the corrosion resistance by improving the compatibility between the plating layers and between the R-T-B powder and the plating layer.

Furthermore, by laminating these plating layers, it is possible to further improve corrosion resistance.

Here, in the present invention, the lit solution plating method was used because Ni-Fe-B
This is because it becomes oxidized. In addition, the heat treatment temperature was set to 40
The reason for setting the temperature to 0 to 1000°C is that at temperatures lower than 400°C, there is almost no effect, and at temperatures above 1000°C, sintering occurs between the powders, resulting in an agglomerated state, and furthermore, the magnetic properties of the powder deteriorate. .

In the present invention, as a result of organic electrolytic plating using an organic solvent in this plating solution, the R-T-B powder can be plated without oxidation, and bonded magnets using this powder have excellent corrosion resistance, and This eliminates the need to coat bonded magnets with oxidation-resistant resin, which was previously required, and can also reduce costs. - Furthermore, deterioration of magnetic properties due to powder oxidation etc. can be prevented, which is extremely useful industrially.

As mentioned above (RT with Nd2Fe+d3 phase as main phase)
-For B-based powder. R-T. whose main phase is R metal or Rrich phase. After plating the R-T-B alloy using an organic electrolytic plating method, Ni, Cu, and AJ are further plated using an organic electrolytic method.
By plating with metals or alloys having oxidation resistance such as, it is possible to produce powder for plastic mags with excellent magnetic properties and corrosion resistance, which is extremely useful industrially.

In addition, this method achieves its purpose by using ordinary Ill-containing electrolytic plating, so it is possible to reduce costs and is also a measure with extremely high mass productivity.

<Example> Examples of the present invention will be described.

Example-1 Using Nd with a purity of 95% or more, electrolytic iron, and ferroboron, A
31Nd-1, OB -F e by medium high frequency heating
Obtain an ingot having a composition of bat (wt%).

Further, this ingot was remelted by high frequency heating in Ar and then injected onto a Cu single roll rotating at the same speed of 35 m/sec to obtain an alloy ribbon with a thickness of about 30 μm. The rice grains were crushed to 32 mesh or less.

This powder was mixed with toluene, ethanol, glopylene carbonate, dimethylformamide and Ni.

Plating thickness 5 to IO using organic electrolytic plating using metal salts of AJ, Ti, Fe, Co, Zn, Mo, and Cu.
Plating should be done so that the thickness is μm.

Furthermore, after mixing these powders so that the mixing ratio of powder and epoxy w fingers was 93 near by weight, 30 KO
Compression molding was carried out at a pressure of 5 tons/d in a magnetic field of Furthermore, it was heated at 100 to 120° C. for 1 hour to produce a compression molded bonded magnet.

In addition, as a comparative example, a bonded magnet was produced using powder that was not plated in the same manner as above.

Table 1 shows the metal or alloy plated on the powder, the magnetic properties, and the 80°C x 90% R, H test results.

From Table 1, it can be seen that the bonded magnet using the powder subjected to organic electrolytic plating according to the present invention has extremely excellent corrosion resistance and excellent magnetic properties.

Example-2 26.8Nd- using Nd, Fe, and B with a purity of 95% or more
An ingot having a composition of 1,0B-Febal (wt%) was obtained by high-frequency melting in Ar.

This ingot was coarsely pulverized with a disk mill and then finely pulverized with a jet mill to an average particle size of 20 to 30 μm.

This powder was applied to Nd metal, 90Nd10Fe, 9O in a methanol-neodymium chloride-boric acid organic solution plating bath.
Tightening was performed using three types of Nd-9,5Fe-0,58 (vt%) as anodes. (Three types of plating) The film thickness at this time was about 1 μm. Subsequently, each powder was plated with Ni in a bath of methanol-Ni acetate-boric acid. The film thickness was 5 to 7 μl.

After mixing 25vol 1% of epoxy resin with these powders,
Molding was carried out under a pressure of 5 tons/- in a magnetic field of 25 kOe.

The temperature was further maintained at 100 to 120°C for 1 hour.

As a comparative example, commercially available MQ1 type powder manufactured by GM was pulverized to 20 to 30 μl, and then 25 VO 1% of epoxy resin was mixed therein in the same manner as described above to produce a bonded magnet.

Magnetic properties and salt spray test (JIS-23
71) for 72 hours and the results are shown in Table 2.

From Table 2, it can be seen that the bonded magnets using the powder according to the present invention have significantly improved magnetic properties compared to conventional ones, and are also excellent in corrosion resistance.

Example-3 Nd metal, Nd-Fe, Nd obtained in Example-2
-The powder coated with Fe-8 and Ni was heat treated in a vacuum at a temperature of 300 to 1100'C. Further, add 25v of epoxy resin to this powder as in the example.
Mix 1% o and mold it under a pressure of 5tOn/cd in a magnetic field of 25kOe. Furthermore, to harden the epoxy resin,
The temperature was maintained at 100-120°C.

FIG. 1 shows the magnetic properties when the heat treatment temperature and the composition of the plated Nd-Fe.B alloy were varied.

As can be seen from Figure 1, the heat treatment temperature was 400 to 100.
It can be seen that the magnetic properties are improved between 0°C. Moreover, at 1100° C., the powders were stuck together and were no longer powders, so they could not be used as samples.

Example-4 26.8Nd-1,0B-Feb prepared in Example-2
A powder having a composition of al (wt%) was plated with Nd metal as the th layer in the same manner as in Example-2.

Furthermore, Ni, Cu, and
Aj, Zn, Co, Mo.

Ti metal and Ni-Zn, Fe-Co, Aj-Cu,
Alloy plating of Mo-Fe and Ti-Aj was applied. At this time, the film thickness was set to 5 to 10 μl.

These powders were mixed with an epoxy resin, molded and heated in a magnetic field, and cured in the same manner as in Example 2 to produce a bonded magnet.

When we measured the magnetic properties of these bonded magnets, we found that B r
12. O~12.4kg (BH)nax27~3
08GOe, +Hc was 8.0 to 10.2 kOe.

In addition, these bonded magnets and the G of the comparative example used in Example-2
A bonded magnet made using MQ-1 powder manufactured by M Company was subjected to a salt spray test for 72 hours based on JIS-2371.
provided. The results are shown in Table 3.

It can be seen from Table 3 that all bonded magnets according to the present invention have excellent corrosion resistance.

Table 3 ◎ - 〇 - 8 - × - No change A very small amount of rust is observed Some rust is observed Red rust is exposed on the entire surface Although only Nd-Fe-B was mentioned, rare earths including Y It can be easily inferred that the same thing can be expected for the RT.B system using element R and transition metal T.

Furthermore, it can be easily inferred that any metal or alloy may be used as the metal to be plated as long as it can be plated in an organic solvent and has corrosion resistance. In this example, after plating Nd metal, Ni is applied to this surface.
, Cu, AN, Zn.

Although plating was performed with a metal or alloy made of at least one of Co, Mo, and Ti, those skilled in the art will easily understand that in the present invention, the plating film made of this metal or alloy may have a multilayer structure. This is understandable.

<Effects of the Invention> As described above, according to the present invention. Ni, AJ! is coated on R-T-8 alloy powder with R2T and 4B phases as main phases by a method of electrolytic plating. , Ti, Fe, Co.

By forming a plating layer of one or more of Zn, Mo, Cu, or an alloy, the corrosion resistance of the powder is significantly improved, so bonded magnets using the powder can also be manufactured with extremely excellent corrosion resistance. This is extremely useful industrially as it can prevent deterioration of magnetic properties due to oxidation etc. during the manufacturing process.

Furthermore, the present invention uses R electrolytic plating, which is substantially the same as a normal plating process, so it is advantageous because it can be mass-produced at low cost.

According to the invention. R・T− with R2T14B phase as the main phase
8 alloy powder. RT. whose main phase is R metal or R-rich phase. Rare earth magnet alloy powder and polymer composite for polymer composite magnets that have significantly superior magnetic properties than conventional rare earth magnet alloy powders for polymer composite magnets by plating with R-T-B alloy and organic electrolytic plating method. type rare earth magnet can be obtained.

This is because with conventional powders, in order to obtain a high coercive force, it is necessary to use an isotropic powder, and in order to obtain a high Br due to even higher magnetic anisotropy, a powder with an extremely low coercive force is used. However, in the present invention, Rrich, which is essential for generating high coercive force in R2T and B phase powders with high magnetic anisotropy, has been found to be indispensable.
By plating the phase, this problem could be solved and high properties could be enjoyed.

Furthermore, conventional R-T-B magnet alloy powders were difficult to handle because they were easily oxidized and had to be coated with an oxidation-resistant coating after being made into bonded magnets. Ni, Aj by doing
Since it has become possible to form an alloy layer with excellent corrosion resistance, it is now possible to obtain a powder with extremely excellent corrosion resistance and high magnetic properties, and a polymer composite rare earth magnet using the powder.

Further, the rare earth magnet alloy powder of the present invention can be produced at low cost by using a normal organic electrolytic plating process, and has high mass productivity, making it extremely effective industrially.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the heat treatment temperature and each magnet characteristic of a rare earth magnet according to an example of the present invention. Figure 1--Δ--9ONd-10Fe Metsuki heat treatment I11 (
@C)

Claims (6)

[Claims] 1. R_2T_1_4B (R represents a rare earth element containing Y, and T represents a transition metal.) A rare earth element characterized by having an organic electrolytic plating layer on the surface of the R/T/B alloy powder whose main phase is an intermetallic compound. Magnet alloy powder. 2. The rare earth magnet alloy powder according to claim 1, wherein the organic electrolytic plated layer contains at least one of R, RT, and RTB. 3. The organic electrolytic plating layer is made of Ni, Al, Cu, Zn,
The rare earth magnet alloy powder according to claim 1, comprising a metal layer (including an alloy layer) made of at least one of Co, Fe, Mo, and Ti. 4. R_2T_1_4B (However, R represents a rare earth element containing Y, and T represents a transition metal.) R, R-T, R-T-
A method for producing rare earth magnet alloy powder, comprising a first plating step of electrodepositing a first organic electrolytic plating layer made of at least one type of B. 5. Ni, Al,
At least one of Cu, Zn, Co, Fe, Mo, Ti
5. The method for producing a rare earth magnet alloy powder according to claim 4, further comprising a second plating step of electrodepositing a second organic electrolytic plating layer of a metal (including an alloy) consisting of a seed. 6. A polymer composite rare earth magnet formed by molding the rare earth magnet alloy powder according to claim 1 or 2 using a polymer resin.