JPH01150303A - Magnetic anisotropy type sintered magnet and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an anisotropic rare earth sintered magnet having a complicated shape or a complicated fine structure, and a method for manufacturing the same.

[Conventional technology]

Conventional rare earth magnets are produced by press-forming alloy powder in a mold (with or without an orienting magnetic field) at a pressure of 3-lot/cd and then sintering it, or by hot pressing followed by hot homing to form a sintered body. Creating.

(For example, see Japanese Patent Application No. 57-145072.) There is also a method in which a mixture of rare earth magnet alloy powder and a binder is formed by magnetic extrusion and then sintered to produce a sintered body. (
For example, see JP-A-61-27 [1303] [Problems to be solved by the invention] Among the above-mentioned conventional techniques, in the method using hot press, the sintered body that can be produced has a relatively simple shape (cylindrical, (rings, prisms, plates, etc.), and if you try to create a complicated shape, post-processing is required, which still has its limits and increases costs.

Furthermore, as with the above-mentioned ° method, extrusion molding also yields only a continuum with a relatively pure shape, and furthermore, it requires a step of cutting into a predetermined length after molding, which also increases costs. .

Therefore, in the present invention, a plurality of square holes are drilled in a case-shaped magnet, a molded body or a cylinder in which a magnet part and a non-magnetic metal part are obtained by simultaneous molding, and the wall thickness is uneven depending on the part. The objective is to obtain a magnet body with such a complicated shape. Furthermore, the aim is to obtain a magnet free from distortion, even though it has a complex and irregular shape.

° [Means for solving the problem] The first aspect of the present invention is that the main components are 20 to 45% by weight of R (R is at least one kind of rare earth element), 0.1 to 3% by weight, Oi[t%]
B and 52 to 79.9 fff fi1% of Fe or Fe+Co (however, CO is 1/2 or less of Fe), and the average particle size is 1 to 20 μm.
0 parts and 6 to 14 parts of wax, resin and lubricant as binders, with a sintered density of 90 to 9.
This is a magnetically anisotropic sintered magnet characterized by a magnetic anisotropy of 8%. The second one is mainly composed of 20 to 45% R (R is at least one kind of rare earth element) and the balance is Fes Co5C.
An alloy consisting of u and Zr with an average grain size of 1 to 20μ
100 parts of a powder having m and wax as a binder,
in a range and a mixture of sintered material with 6 to 14 parts of lubricant,
This is a magnetically anisotropic sintered magnet characterized by a sintered density of 90 to 98%. Furthermore, the third one has a main component of 20 to 4
5% by weight of R (R is at least one rare earth element) and O
01-3.0 wt-% B and 52-79.9 wt-% Fe
or Fe+Co (however, Co is less than 1/2 of Fe)
The alloy is pulverized to 1 to 20 μm, and 100
6 to 14 parts of wax, resin, and lubricant as binders are added and mixed into pellets, which are then injection molded into a mold designed to arrange magnet powder anisotropically. A method for producing a magnetically anisotropic sintered magnet, in which the obtained compact is dewaxed and then sintered to a sintered density of 90 to 98%. And the fourth invention has a main component of 20 to 45
% by weight of R (R is at least one kind of rare earth element) and the balance is Fe5Co, Cu, and Zr.
100 parts of the pulverized powder is mixed with 6 to 14 parts of wax, resin, and lubricant as a binder to form pellets, and then a mold is designed so that the magnetic powder is arranged anisotropically. A method for producing a magnetically anisotropic sintered magnet, which is characterized by injection molding the molded body inside the magnet, dewaxing the obtained molded body, and then sintering it to a sintered density of 90 to 98%. .

That is, the present invention uses R-Fe (Co)-B alloy or R[FG, C0% Cus Zrl n-based alloy 1 (in order to obtain a magnetically anisotropic sintered magnet having a rough and precise shape, ■ Setting a specific range of magnetic powder, ■ Creating a specific composition that can be faithfully filled into a precision mold, ■ Creating a mold with a magnetic field strength and orientation that gives a specified anisotropy, and then performing injection molding. The desired objective is achieved by combining the following main requirements: (1) Debinding of the molded body under a specific pressure and subsequent sintering treatment.

In the alloy composition of the present invention, R is Sc.

It is selected from rare earth elements of Y1 lanthanide and actinide series, and elements of Y1 lanthanide series are particularly preferred. R
If the number of magnets is less than 20, high coercive force cannot be obtained, and if it is more than 45, the magnitude of magnetization decreases, making both of them unsuitable for permanent magnets.

Co can be substituted with Fe for the purpose of increasing the Curie temperature, but if more than half of Fefa is substituted, the magnitude of magnetization decreases, making it unsuitable for permanent magnets.

Note that since the alloy is a 2-17 alloy which is well known as the alloy containing CuSZr in the second invention, the reason for adding Cu and Zr is also known, and will not be described in detail here.

Further, in both the first invention and the second invention, Al5SiSTi, V is used for the purpose of increasing the coercive force of the alloy.

Cr, Mn5Cu, Zn5GaSGe, Zr.

Nb, MOS Sn, Sb, HfS
It is also possible to add Ta, W%Bi, etc. (CuSZr is only in the second invention) as necessary.

The average particle size of the alloy powder is 1 μm to 20 μm.
If the powder is made smaller, it will take more time to crush the powder, and there is a risk that the powder will oxidize or catch fire, making it difficult to handle. Furthermore, if the average particle size of the powder exceeds 20 μm, a sufficiently large coercive force cannot be obtained even by heat treatment, and the orientation caused by a magnetic field decreases.

The amount of wax, resin, and lubricant used as binders should be considered based on heat-kneading properties, fluidity, and dewaxing properties. In other words, acrylic and EVA (vinyl acetate), which have polar groups that have good wettability with alloy powder, are used from the viewpoint of heat kneading properties when pelletizing, while polyethylene and polystyrene are used from the viewpoint of fluidity (-formability). Furthermore, stearic acid amide and the like can be mentioned as a lubricant to improve the slippage of the powder. In order to increase the de-fuxing effect while maintaining a more accurate shape, paraffin-based or modified wax is recommended along with acrylic resin.

The proportions of these waxes, resins, and lubricants vary depending on the type, particle size, and particle size distribution of the alloy powder, but the appropriate total amount is 6 to 14 parts per 100 parts of the alloy powder. If it is less than 6 parts, the alloy powder will clog the injection tube during injection molding, and if it exceeds 14 parts, defective products such as mold part warping or deformation will be produced in the dewaxing process or sintering process.

The mixing ratio of wax, resin, and lubricant is 1 to 4 parts of wax and 4.5 parts of resin to 100 parts of alloy powder.
-8 parts, lubricant 0.5-2 parts is suitable.

The density of the sintered magnet of the present invention is preferably in the range of 90 to 98%;
If it is less than 0%, only unsatisfactory characteristics as a magnet will be obtained, and 9
If it exceeds 8%, cracking may occur, which is not preferable.

In the injection molding process of the manufacturing method invention, if the temperature is lower than 90℃, the mixed material will not be injected smoothly, and if the temperature is higher than IH℃, there is a greater possibility of thermal decomposition or excessive fluidity, and the wax component will be injected first. It may be ejected.

Also, the magnetic field strength inside the cavity of the special injection mold is 10k.
It is preferable to set it to Oe or more, but if it is less than IQkOc, the orientation of the alloy powder is not sufficient.

Also, the dewaxing process is preferably 1 kg/cd
The temperature is raised to 3-400°C under the following pressure. By dewaxing under such conditions, it is effective to maintain the shape of the molded body, to facilitate wax elution, and to shorten the dewaxing process, which tends to take a long time. If the heating rate is less than 3°C/hr, it is not practical in terms of productivity;
■If the temperature exceeds 5°C/11r, the shape of the molded product may collapse.

Furthermore, if the temperature is increased to 400° C. or higher, the compact often collapses due to dewaxing and returns to the original alloy powder.

Sintering is carried out under an inert gas pressure of 1 kg/cd or more.
000 to 1.2 (preferably carried out at 10°C). Pressurization with inert gas prevents evaporation of alloying elements. The sintering temperature is 1
．． At temperatures below 000°C, the density of the sintered body becomes less than 90%,
Moreover, if the temperature exceeds 1,200°C, the density will exceed 9 g%, which may cause cracking, etc., which is inappropriate.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples.

Example 1 25% by weight S m S 18% by weight Fe, 5% by weight Cu
An alloy with a composition consisting of s2.2 wt% 1 part was added and pelletized using a pressure kneader (N2 gas 5 kg/cd, 140°C x lhr).

Figure 1! 1. A complex-shaped magnet shown in Fig. 2 (radial orientation magnetic field - IQkOc, outer diameter a - 60 fin, tip circle 1
k b -40mm, tooth height c -5in, tube length d-2
Using an injection molding machine equipped with a mold for molding 0 mm), the nozzle temperature was adjusted to 130° C., and injection was performed at a pressure of 520 kg/c+J to obtain a green molded product.

After measuring the dimensions of each part of the green molded body, place it in a dewaxing furnace, flow Ar gas while maintaining it at 2 kg/c+J, raise the temperature to 400°C at a rate of 5°C/hr, hold it at 400°C for 1 hour, and then cool it. did. At this point, 90% of the binder had been removed and the shrinkage measured by the outer diameter was almost 0.

Next, this was placed in a sintering furnace, and after being vacuumed to 5 x 104 Torr, the temperature was raised from room temperature to 600°C in 2 hours (Ar gas 1kg/cl#) and held there for 1 hour.At this point, the binder was removed. 1. The temperature was raised to 180° C. in 1 hour. After being held at 1,180°C for 2 hours, it was cooled to room temperature with Ar gas, then at 800°C for 2 hours, and then slowly cooled to 400°C at a rate of 0.8°C/min.
The mixture was held for 4 hours and then cooled in the furnace. Each AJl constant value for the sintered body was as shown in Table 1. r indicates the magnetic field alignment direction of the sample, and 2 indicates that /lII is set in the direction perpendicular to it (thickness direction).

Table 1 Example 2 28.5% by weight Nd, 3.5% by weight Dy, 1.
An alloy having a composition of 5% by weight B, 8% by weight Co, residual Fe, and unavoidable impurities was ground to give an average particle size of 3.8 μm. On the other hand, 99.99% Cu powder (average particle size lOμm)
were prepared, pelletized according to the specifications in Table 2, and integrally molded into the shapes shown in FIGS. 3 and 4 using a two-screw injection molding machine. That is, in the figure, 2 is the magnet part (radial orientation), 3 is C
This is a magnet holding part made of u.

Table 2 All binders are in proportion to 100 parts of each of the alloy powder and Cu powder.

This green sheet molded body was
Under pressure of cd, the temperature was raised to 350°C at a rate of 10°C/hr, and
It was held at 50° C. for 1 hour to dewax. Next, this was transferred to a sintering furnace, and the temperature was raised to 600 °C in 2 hours at a vacuum level of 4 to 5 × 1O'' Torr, and after holding there for 1 hour,
The temperature was raised to 1,075°C over 1 hour under a pressure of 2 kg/c- of Ar, and after being maintained for 3 hours, it was rapidly cooled with gas.

The sintered body was taken out of the furnace, the magnet part and the magnet holding part were cut out, and the densities were measured, and the results were 95% and 99%, and the shrinkage percentages were as shown in Table 3.

Table 3 Furthermore, the radial direction (magnetic field orientation direction -'), circumferential direction (-X), and height h' direction (-z
) were as shown in Table 4.

〔Effect of the invention〕

According to the present invention, a sintered magnet with a complicated and precise shape and without distortion can be easily obtained.

[Brief explanation of the drawing]

Fig. 1 is a front view of a magnet according to one embodiment of the present invention, Fig. 2 is a side view of .1 in Fig. 1, Fig. 3 is a front view of a magnet of another embodiment, and Fig. 4 is a FIG.

Claims (8)

[Claims] (1) The main components are 20-45% by weight of R (R is at least one rare earth element), 0.1-3.0% by weight of B, and 5% by weight of B.
2 to 79.9% by weight of Fe or Fe+Co (however, C
A sintered material of a mixture of 100 parts of powder having an average particle size of 1 to 20 μm and 6 to 14 parts of wax, resin, and lubricant as a binder. , a magnetically anisotropic sintered magnet characterized by having a sintered density of 90 to 98%. (2) The main component is 20 to 45% by weight of R (R is at least one rare earth element), and the balance is Fe, Co, Cu, and Zr.
A sintered material consisting of a mixture of 100 parts of powder having an average particle size of 1 to 20 μm and 6 to 14 parts of wax, range, and lubricant as binders, with a sintered density of 90 to 98%. A magnetically anisotropic sintered magnet characterized by: (3) The main components are 20 to 45% by weight of R (R is at least one rare earth element), 0.1 to 3.0% by weight of B, and 52
~79.9% by weight of Fe or Fe+Co (however, C
(o is 1/2 or less of Fe) is pulverized to 1 to 20 μm, and to 100 parts of the pulverized powder, 6 to 14 parts of wax, resin, and lubricant are added as a binder and mixed to form pellets. Injection molding is carried out into a mold designed to arrange magnet powder anisotropically, and then the obtained molded body is dewaxed and sintered so that the sintered density is 90 to 98%. A method for manufacturing a magnetically anisotropic sintered magnet, characterized by: (4) The main component is 20 to 45% by weight of R (R is at least one rare earth element), and the balance is Fe, Co, Cu, and Zr.
The alloy is pulverized to an average particle size of 1 to 20 μm, and 6 to 14 parts of wax, resin, and lubricant are added as a binder to 100 parts of the pulverized powder to form pellets. A method of manufacturing a magnetic material that is characterized by injection molding into a mold designed to arrange the particles, and then dewaxing the obtained molded product and sintering it to a sintered density of 90 to 98%. A method for manufacturing a oriented sintered magnet. (5) Injection molding is carried out at 90 to 160°C and under pressure of 1 kg/cm^2 or more.
4) A method for producing a magnetically anisotropic sintered magnet as described in item 4). (6) The cavity magnetic field strength in the injection mold is 10kO
The method for producing a magnetically anisotropic sintered magnet according to claim 3 or 4, wherein the injection nozzle temperature is 100 to 140° C. (7) Claim (3) or (4) wherein dewaxing is carried out by heating up to 400°C at a rate of 3 to 15°C/hr under an inert gas pressure of 1 kg/cm^2 or less
A method for producing a magnetically anisotropic sintered magnet as described in . (8) The sintering is carried out at 1,000 to 1,200°C under an inert gas pressure of 1 kg/cm^2 or less (
The method for manufacturing a magnetically anisotropic sintered magnet according to item 3) or item (4).