JP3028337B2 - Rare earth magnet alloy powder, method for producing the same, and polymer composite rare earth magnet using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an RTB-based permanent magnet alloy powder containing an R ₂ T ₁₄ B intermetallic compound represented by Nd ₂ Fe ₁₄ B as a main phase. More particularly, the present invention relates to a powder, a method for producing the same, and a polymer composite type rare earth magnet using the same.

<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. The Nd / Fe / B permanent magnets are roughly classified into two types: sintered magnets and plastic magnets (also called pramags).

Among them, the manufacturing method and composition of sintered magnets are almost established, and products having high magnet properties are manufactured on industrial lines and provided to users.

However, in the field of plastic mags, at present, the magnet properties are low, and the manufacturing process thereof has not been established at present. Therefore, Pramag products having high magnetic properties satisfying users are not provided.

At present, as alloy powders for Nd / Fe / B-based plastic mags, liquid quenched alloy powder obtained by quenching alloy melt (referred to as first alloy powder), powder obtained by hot working this liquid quenched alloy powder (second alloy powder) ) And powder obtained by pulverizing a sintered body or an ingot (referred to as a third alloy powder).

However, although the first alloy powder has a high Hc, the powder is isotropic, so the magnetic field orientation cannot be performed, and the Sm-Co
Plamag with higher (BH) max than the system cannot be produced. Further, a second alloy powder obtained by hot working a second liquid quenched alloy powder has been developed to further improve this drawback and give the powder anisotropy. In this method, an isotropic liquid quenched alloy powder is hot-worked so as to have a certain type of texture and to achieve shape anisotropy. According to this method, a certain degree of magnetic field orientation effect is produced and Br is also improved, but the effect is small and Hc is further reduced. Moreover, the process is complicated and the cost is greatly increased, which is not industrially preferable. Third
The method of using a pulverized powder of a sintered body or an ingot, which is the method of (1), is a method in which a conventional method of producing a Sm / Co-based pramag is directly applied to Nd / Fe / B. However, in this method, Br can be improved by magnetic field orientation, but Nd.Fe.B
The powder cannot be used as a powder for plastic mag because it causes a significant deterioration of Hc due to pulverization. This is due to the decrease in Hc caused by the deteriorated layer on the surface of the powder generated during the pulverization, and the largest cause is that the pulverized powder is a neodymium-rich (Ndrich) phase that is indispensable for generating the coercive force of Hd, Fe and B This is because it is not always wrapped.

That is, in the present magnet, the Nd ₂ Fe ₁₄ B phase
When wrapped in a phase, the Ndrich phase is considered to generate a high coercive force because the movement of the domain wall is trapped.
Therefore, when the magnetic phase is exposed on the powder surface, the domain wall is freely inverted from this position, and the coercive force is significantly deteriorated. Furthermore, this Nd2Fe14B phase alone cannot be a magnet.

Further, since the present magnet powder contains a rare earth element or Fe as a main component which is extremely active in the atmosphere, it is easily oxidized.

In addition, especially during injection molding, the temperature is raised to around 200 ° C in order to lower the viscosity of the polymer and improve the moldability, but this also has the disadvantage that the magnet characteristics are degraded due to high temperature oxidation. Was.

Furthermore, even after molding, since there is a part where the powder surface is exposed on the surface of the plastic mag, even during use,
Since oxidation progresses from this part, the surface of the powder is subjected to various chemical treatments in advance to give it oxidation resistance, but it is still not enough, and the surface of the molded pramag is intended to have more oxidation resistance. The actual condition is that the resin coating is applied, which increases the cost.

[Problems to be Solved by the Invention] That is, from the points described above, all of Nd, Fe, B
It was not suitable as a powder for plastics.

Further, since the present alloy contains an element which is easily oxidized in the atmosphere, such as Nd and Fe, its alloy, alloy powder, and sintered body are oxidized by the humidity in the atmosphere and generate rust.

Therefore, it is difficult to handle these alloy powders, and the properties of the magnet powder are degraded due to oxidation of the magnet powder in a process such as heat curing during the production of the bonded magnet. In addition, even after making the bond magnet, because the powder is exposed on the surface,
Oxidation proceeds from here, not only deteriorating the magnet properties, but also contaminating peripheral parts with this oxide and even breaking down the bonded magnet due to extreme oxidation.

As a countermeasure for this, the powder is treated with a Ti coupling or a silane coupling agent, but in reality it is almost ineffective. Furthermore, a method has been proposed in which a bonded magnet is formed and then its surface is coated with an oxidation-resistant resin, but it cannot be completely coated with a complicated shape or an elongated cylindrical shape formed by injection molding or the like. In some cases, it is not suitable as a countermeasure.

The technical problems of the present invention are as follows: (1) By producing a powder in which an Nd ₂ Fe ₁₄ B phase is wrapped by an Ndrich layer, the effect of magnetic field orientation can be increased to increase the Br and
Preparing a powder of _I H _C.

(2) Further, an oxidation resistance is provided by forming an organic electrolytic plating layer of Ni, Cu or the like on the surface of the powder.

By achieving the above two points by an organic electrolytic plating method, a powder for a rare earth pramag having high magnetic field orientation, high coercive force, and excellent oxidation resistance and a method for producing the same are provided at low cost. It is in.

Another technical problem of the present invention is to provide a bond magnet R / T / B system having excellent corrosion resistance by applying a plating coating of a metal or alloy having excellent corrosion resistance to the bonded magnet powder by organic electrolytic plating. An object of the present invention is to provide an alloy powder and a method for producing the same.

Still another object of the present invention is to provide a polymer composite rare earth magnet using these RTB-based alloy powders and a method for producing the same.

[Means for Solving the Problems] According to the present invention, R ₂ T ₁₄ B (where R represents a rare earth element containing Y and T represents a transition metal) has an intermetallic compound of R · T as a main phase. -A first plating layer is provided on the surface of the B-based alloy powder, and the first plating layer is formed of an R, RT alloy, and an RT alloy.
-B alloy and at least one of the foregoing RT alloy and R
A rare earth magnet alloy powder characterized in that the -TB alloy has an R-rich phase as a main phase.

Further, according to the present invention, in the rare-earth magnet alloy powder, Ni, Cu, Co, Fe, M
o, and at least one of Ti, or Zn and Al
And a second plating layer comprising a metal layer (including an alloy layer) made of at least one of Ni, Cu, Co, Fe, Mo, and Ti. An alloy powder is obtained.

Further, according to the present invention, there is provided a polymer composite type rare earth magnet obtained by molding any one of the rare earth magnet alloy powders using a polymer resin.

Further, according to the present invention, R ₂ T ₁₄ B (where R represents a rare earth element containing Y and T represents a transition metal) The surface of an R · T · B-based alloy powder having an intermetallic compound as a main phase. , R, RT alloy,
It is composed of at least one kind of R-T-B alloy, and the R-T alloy and the R-T-B alloy electrodeposit a first organic electrolytic plating layer having an R-rich phase as a main phase. A method for producing a rare earth magnet alloy powder characterized by including a first plating step is obtained.

According to the present invention, in the method for producing a rare-earth magnet alloy powder, Ni, Cu,
One of Co, Fe, Mo, and Ti, or Zn and T
a second metal layer (including an alloy layer) composed of at least one of i and at least one of Ni, Cu, Co, Fe, Mo, and Ti
And a second plating step of electrodepositing the organic electrolytic plating layer of (1).

Here, the method for producing a rare earth magnet alloy powder of the present invention preferably includes a heat treatment step of performing a heat treatment at 400 to 1000 ° C. as a step after the first or second organic electrolytic plating step.

According to the present invention, there is provided a method for producing a polymer composite type rare earth magnet, wherein the rare earth magnet alloy powder obtained by any one of the methods for producing a rare earth magnet alloy powder is further mixed with a polymer resin and molded. Is obtained.

Here, molding using a polymer resin in the present invention means that a polymer is mixed with a raw material powder and compression molded, extruded or injection molded to obtain a molded body, or molded by compression molding from the raw material powder. Coating or impregnating the body with a polymeric resin.

As mentioned above, powder for Nd / Fe / B plastic
One utilizing the property of high coercive force of liquid quenched alloy powder,
Nd-Fe-B sintered compacts or ingots utilizing high magnetic field orientation of the pulverized powder have been proposed.
High Br and high coercivity sintered compact Nd ・ Fe due to its magnetic field orientation
-It is not possible to make use of both the characteristics of the B magnet.

Apart from that, the extremely large problem of its oxidation resistance, which is a serious problem in mounting, has not been solved. As a result of various studies, the present inventors have found that Nd can be plated on a Nd2T14B phase by using an organic electrolytic plating method, and have reached the present invention.

Further, the present inventors have found that various metals or alloys can be plated on the RTB-based alloy powder by using organic electrolytic plating using an organic solvent, and have reached the present invention.

That is, since the RTB-based magnet alloy is an alloy that is very easily oxidized, it is impossible to perform plating using a normal aqueous solution because the alloy powder is oxidized during the plating process. Furthermore, focusing on the fact that Nd metal does not oxidize in an organic solvent, the oxidation-resistant plating (Ni, Cu, etc.) is applied to the surface of the Nd metal by organic electrolytic plating to obtain the magnet powder excellent in oxidation resistance of the present invention. It was possible to invent.

That is, according to the present invention, R-T of a main phase of Nd metal or predominantly Ndrich phase Nd ₂ Fe ₁₄ B phase to R · T · B alloy powder as a main phase, the R-T-B alloy high Br by high uniaxial magnetic anisotropy having the Nd ₂ Fe ₁₄ B phase by plating by an organic electrolytic plating method, and both characteristics of a high coercive force obtained by wrapping the Nd ₂ Fe ₁₄ B phase by Rrich phase It is possible to obtain a powder that has been utilized.

Furthermore, in the state of this powder, the oxidation resistance is poor because the powder surface is in an R-rich phase, but the oxidation resistance is further improved by applying a plating of Ni, Cu, etc. by an organic electrolytic plating method. It can be given. Moreover, by further heat treating these powders at a temperature of 400 to 1000 ° C., the coercive force can be further improved,
Corrosion resistance can also be improved by improving the compatibility between the plating layer and the R, T, B powder and the plating layer.

Further, by laminating these plating layers, the corrosion resistance can be further improved.

Here, the reason why the organic electrolytic plating method is used in the present invention is that Nd, Fe, and B are oxidized by water in plating with a normal aqueous solution. Also, heat treatment temperature is 400 ~ 100
The reason why the temperature is set to 0 ° C is that there is almost no effect at temperatures lower than 400 ° C, and sintering between powders occurs at 1000 ° C or higher,
This is because the particles are in an agglomerated state, and the magnetic properties of the powder are also deteriorated.

In the present invention, as a result of performing organic electrolytic plating using an organic solvent for the plating solution, the R, T, and B powders can be plated without being oxidized, and the bonded magnet using the powders has excellent corrosion resistance. This eliminates the need for a coating of an oxidation-resistant resin or the like on the bonded magnet, which has been required until now, so that the cost can be reduced.

Further, deterioration of magnet properties due to oxidation of the powder and the like can be prevented, which is extremely useful industrially.

As described above, the R-T, R- phase having the R metal or the Rrich phase as the main phase is added to the RTB-based powder having the Nd ₂ Fe ₁₄ B phase as the main phase.
Plamag powder with excellent magnet properties and corrosion resistance by plating a TB alloy with an organic electrolytic plating method and then plating an oxidation-resistant metal or alloy such as Ni, Cu, or Al by the organic electrolytic method. Can be produced, which is extremely useful industrially.

In addition, in this method, the purpose is achieved by using ordinary organic electrolytic plating, so that the cost can be reduced and mass production is extremely high.

<Example> An example of the present invention will be described.

Example 1 26.8Nd-1.0B-Febal (wt.) Using Nd, Fe, B having a purity of 95% or more.
%) Was obtained by high frequency melting in Ar.

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

Nd metal, 90Nd-10Fe, 90Nd-9.5Fe- in a methanol-neodymium chloride-boric acid organic solution plating bath.
Plating was performed using three types of 0.5B (wt%) as anodes. (Three types of plating) At this time, the film thickness was about 1 μm. Subsequently, each powder was subjected to Ni plating in a bath of methanol-Ni-acetate-boric acid. This film thickness is 5
７7 μm.

After mixing 25vol% of epoxy resin with these powders, 25k
It was molded at a pressure of 5 ton / cm2 in a magnetic field of Oe. Further 100-120
C. for 1 hour. As a comparative example, a commercially available GM
After pulverizing the MQ-1 type powder made by the company to 20-30 μm, 25% by volume of epoxy resin is mixed by the same method as above,
A bonded magnet was produced.

Magnet properties and salt spray test of these samples (JIS-2371)
Is shown in Table 1 for 72 hours.

From Table 1, the bonded magnet using the powder according to the present invention is:
It can be seen that the magnet properties are remarkably improved as compared with the conventional one and the corrosion resistance is excellent.

Example 2 Nd metal, Nd.Fe, Nd.Fe.B obtained in Example 1
Powder and Ni-plated powder in vacuum
The heat treatment was performed at a temperature of 11100 ° C. Further, this powder was mixed with 25 vol% of an epoxy resin in the same manner as in the example, and was molded at a pressure of 5 ton / cm ^{2 in} a magnetic field of 25 kOe. In order to further cure the epoxy resin, it was kept at a temperature of 100 to 120 ° C.

FIG. 1 shows the magnet properties when the heat treatment temperature and the composition of the plated Nd.Fe.B alloy were changed.

As can be seen from FIG. 1, the heat treatment temperature is 400-1000 ° C.
It can be seen that the magnetic properties are improved between the two. Also,
At 1100 ° C, the powder was bound together and was no longer a powder, so it could not be used as a sample.

Example-3 Nd metal was plated as a first layer on the powder having the composition of 26.8Nd-1.0B-Febal (wt%) prepared in Example-1 as in Example-1. Furthermore, for this powder,
Ni, Cu, AL, Zn, Co, Mo, Ti metals and Ni-Z by organic electrolysis
Alloy plating of n, Fe-Co, Al-Cu, Mo-Fe, Ti-Al was applied. At this time, the film thickness was set to 5 to 10 μm.

Epoxy resin mixed with these powders as in Example-2,
The molded magnet was heated and cured in a magnetic field to produce a bonded magnet.

When the magnet properties of these bonded magnets were measured, Br1
_{2.0~12.4kG, (BH) max27~30MGOe, I} H C is 8.0~10.2kO
e.

In addition, these bonded magnets and the comparative example used in Example-1
Bond magnets made using GM's MQ-1 powder
A salt spray test was conducted for 72 hours based on JIS-2371. Table 2 shows the results.

Table 2 shows that all of the bonded magnets according to the present invention have excellent corrosion resistance.

Although only Nd.Fe.B has been described above, it can be easily inferred that the same can be expected in an R.T.B system using a rare earth element R including Y and a transition metal T.

Further, it can be easily inferred that any metal or alloy that can be plated in an organic solvent and has corrosion resistance may be used for the metal to be plated. In this example, after plating Nd metal, Ni, Cu,
Although plating of a metal or an alloy of at least one of A, Zn, Co, Mo, and Ti has been performed, in the present invention, a plating film of the metal or the alloy may include a film having a multilayer structure. It is easily understood by those skilled in the art.

<Effects of the Invention> As described above, according to the present invention, an R • T • B alloy powder having an R ₂ T ₁₄ B phase as a main phase is treated with N by an organic electrolytic plating method.
By forming a plating layer of at least one of i, Al, Ti, Fe, Co, Zn, Mo, and Cu or an alloy, the corrosion resistance of the powder is remarkably improved, and the bonded magnet using the powder is also remarkably excellent in corrosion resistance. Can be manufactured, and deterioration of magnet properties due to oxidation or the like during the manufacturing process can be prevented, which is extremely useful industrially.

Further, in the present invention, since the same organic electrolytic plating as that in the ordinary plating step is used, low cost and mass production are possible, which is advantageous.

According to the present invention, an R-T-R-B alloy powder having an R2T14B phase as a main phase is provided with an R-T, R-
Rare earth magnet alloy powder for polymer composite magnets and polymer composite rare earths, which have remarkably excellent magnet properties compared to conventional rare earth magnet alloy powders for polymer composite magnets by plating with a TB alloy by an organic electrolytic plating method A magnet is obtained.

This is because conventional powders must use isotropic powder to obtain high coercive force, and use powder with extremely low coercive force to obtain high Br due to higher magnetic anisotropy. Although it was unavoidable, by plating the Rrich phase essential for generating high coercive force on R ₂ T ₁₄ B phase powder having high magnetic anisotropy according to the present invention, This problem can be solved and high characteristics can be enjoyed.

Further, conventional RTB-based magnetic alloy powders are liable to be oxidized, so that they are difficult to handle, and must be coated with an oxidation-resistant coating after being made into a bonded magnet. This makes it possible to form an alloy layer having excellent corrosion resistance, such as Ni and Al, so that it is possible to obtain a powder having excellent corrosion resistance and high magnet properties and a polymer composite rare earth magnet using the same. Things.

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 is highly effective in industry because of high mass productivity.

[Brief description of the drawings]

FIG. 1 is a diagram showing the heat treatment temperature of a rare earth magnet according to an embodiment of the present invention and the properties of each magnet.

Continuation of the front page (56) References JP-A-62-284002 (JP, A) JP-A-1-225102 (JP, A) JP-A-62-213208 (JP, A)

Claims (7)

(57) [Claims] (1) R ₂ T ₁₄ B (where R is a rare earth element containing Y,
T represents a transition metal. ) R having an intermetallic compound as a main phase
A first plating layer on the surface of the TB alloy powder, wherein the first plating layer contains at least one of R, RT alloy, and RTB alloy; RT alloy and RT-
The rare earth magnet alloy powder, wherein the B alloy has an R-rich phase as a main phase. 2. The rare-earth magnet alloy powder according to claim 1, further comprising Ni, Cu, Co, Fe, Mo,
And a metal layer (including an alloy layer) of at least one of Zn and Al, or at least one of Ni, Cu, Co, Fe, Mo, and Ti A rare earth magnet alloy powder comprising a second plating layer made of: 3. A polymer composite rare earth magnet obtained by molding the rare earth magnet alloy powder according to claim 1 using a polymer resin. 4. R ₂ T ₁₄ B (where R is a rare earth element containing Y,
T represents a transition metal. ) R having an intermetallic compound as a main phase
-The at least one of R, R-T alloy and R-T-B alloy is formed on the surface of the TB alloy powder, and the R-T alloy and the R-T alloy
A method for producing a rare earth magnet alloy powder, comprising a first plating step of electrodepositing a first organic electrolytic plating layer in which the -B alloy has an R-rich phase as a main phase. 5. The method for producing a rare earth magnet alloy powder according to claim 4, wherein the surface of the first organic electrolytic plating layer is N
consisting of one of i, Cu, Co, Fe, Mo, and Ti, or Zn
Metal layer (including alloy layer) consisting of at least one of Al and Al and at least one of Ni, Cu, Co, Fe, Mo, and Ti
A second plating step of electrodepositing the second organic electrolytic plating layer described above. 6. The method for producing a rare earth magnet alloy powder according to claim 4, further comprising a step of performing a heat treatment at 400 to 1000 ° C. after the first or second plating step. Manufacturing method of magnet alloy powder. 7. A rare earth magnet alloy powder obtained by the method for producing a rare earth magnet alloy powder according to claim 4 is further mixed with a polymer resin and molded. A method for producing a polymer composite type rare earth magnet.