JPS59125603A - Permanent magnet material and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain the magnet material excellent in all of sintering property, dimensional accuracy and magnetic characteristics by injecting and molding powder consisting of an alnico (aluminum-nickel-cobalt) alloy group permanent- magnet material by using at least two kinds of organic materials, removing a binder and sintering a shape. CONSTITUTION:Alloy powder consisting of Al, Ni, Co, Cu, Ti, Nb, V and Fe and the binder consisting of HDPE, APP (high molecular weight) and APP (low molecular weight) are heated and mixed at a ratio of 98:5:9:3, and formed to a columnar shape by an injection molding machine. The shape is degreased through heating, sintered, solution heat treated in a magnetic field, quenched and aging-treated. A thermosetting resin, a natural resin, a rubber, an elastomer, etc. may be used besides the combination of a thermoplastic resin, a slip additive and a plasticizer as the organic materials, a heating loss curve is measured previously by a differential thermal analyzer, and a plurality of the binders are combined properly. Accordingly, the powder, the binders and the organic materials are mixed so as to be degreased at every approximately fixed quantity to a gradient of a heating temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an alnico yarn permanent magnet material obtained by a powder metallurgy method, and more specifically, a mixed material consisting of the permanent magnet powder and a binder is molded with high dimensional accuracy by an injection molding method. The present invention relates to a permanent magnet material that is formed into a molded body, contains a specific element to obtain high-density sinterability, and has desirable magnetic properties, and a method for producing the same.

Alnico yarn permanent magnets are generally manufactured by a casting method.

The manufacturing conditions vary depending on the composition, but for example, the weight ratio of At
7-12%, 1'J110-20%, 0o28-30%
Qul~7%, Ti4. O ~ 5.5% as the main component, and at the same time as additives 0002 ~ 0.2%, SO,l
In an alnico magnet containing NLO%, Bib05~30%, T140~5.5%, and the balance essentially consisting of Fe,
The pouring temperature path is 1700C, and after solution treatment at 1200C or higher, cooling in a magnetic field at a cooling rate of 01-09C/S''c, holding in a magnetic field at a constant temperature about 10-5oC lower than the Curie point, and then 550-fr50c. Magnet material is obtained by aging before and after.

On the other hand, powder metallurgy technology has been developed as a manufacturing method for general metal parts, and has been widely applied to automobile parts, electrical parts, mechanical parts, etc., and its effects are well known. If the powder metallurgy method, that is, the sintering method is applied to alnico alloys (hereinafter referred to as the main alloys), the process up to the solution treatment of the molten material is an extremely simple process of powder mixing, shaping and sintering, and the desired result can be achieved. A shaped magnet material can be obtained, or it can be finished into a shape close to it.

However, even when the permanent magnet material of this alloy is melted and cast, or even sintered using the normal press forming method, it is difficult to produce products with complex shapes or products that require a high degree of dimensional accuracy. When manufacturing, it is necessary to finish and process the material.

One of the features of the permanent magnet material of the present invention is that an injection molding method is applied to the molding process in order to produce a product with such a complicated shape and a product that requires a high degree of dimensional accuracy. As is well known, the injection molding method has demonstrated its power in the field of plastic molding, and the tolerance ±αQ 1
It is possible to obtain a molding accuracy of about m. In order to apply the injection molding method to this alloy, it is important to create a molding mix (compound) with a high content of metal powder, and the following knowledge is required for this purpose. Namely, (1) creation of a metal powder with high filling of 65 to 85% of the theoretical density, (2) selection of a binder that matches good fluidity, molding strength, and degreasability, and (3)
After extensive study on the selection of a low-additive material that satisfies these conditions, we were able to obtain a compound suitable for injection molding.

In addition, in order to use the present alloy as a permanent magnet material, it is necessary not only to obtain a high degree of dimensional accuracy by injection molding, but also to have magnetic properties of μs. In general, in magnetic materials manufactured by the sintering method, the apparent @!
There is a close relationship between 1R and magnetic properties; for example, the residual magnetic flux density (Br) is proportional to the magnetic property. Therefore, in order to obtain a material with immersed magnetic properties, it is important to make the density as close to the theoretical density as possible.

The composition of the present alloy is not particularly limited, and includes the basic composition and additive system of known alnico magnets. That is, the Aχ amount ratio is At6~12%N11(j-2
8%, 005~35%, CuO~7%, T soil ○~8%Other additives include Oo/-0,2
%, 80-1%, and 0-4% Nb, with the remainder being Fe, and is known to have unique magnetic properties. Furthermore, it has been reported (Japanese Patent Publication No. 47-44409) that the coercive force Hc and the maximum magnetic energy (BH)m are significantly increased by adding 01 to 05% of ■.

That is, regardless of the composition of the alnico magnet, the present invention involves mixing or kneading powder made of the magnet material with a binder, injection molding the alnico yarn permanent magnet material, and then removing the inder, furnace, and curing the alnico yarn permanent magnet material. It is a permanent magnetic material characterized by being made of.

By the way, when applying the injection molding method to this alloy, the fl
) In addition to those mentioned in +21 and (3), the selection of organic materials including the degreasing process is extremely important. Although polystyrene and the like are often used as organic materials for injection molding, most synthetic resins are used, and each has its advantages and disadvantages. The organic material added for molding is generally a combination of a thermoplastic resin, a lubricant, and a plasticizer, but thermosetting root fat, natural resin, rubber, elastomer, etc. can also be used. Among these, the selection of the main thermoplastic resin is particularly important, and the selection of the thermoplastic resin is particularly important, considering the cost of the resin, compatibility with the alloy (wettability), heat fluidity (moldability), thermal decomposability, and decomposition residue components. etc. are particularly important points of this molding method.

The binder used needs to be decomposed or volatilized in the binder removal (degreasing) step, and an organic compound is used for this purpose. One type of binder is sufficient, but in order to perform the binder removal process smoothly, binders, lubricants,
Prepare multiple binders that act as plasticizers,
By measuring the heating loss curve in advance using a differential thermal analyzer, and then appropriately combining these multiple binders, it is possible to mix them so as to degrease a substantially constant amount with respect to the heating temperature gradient. desirable. Further, depending on the type of binder, a surface modifying material may be added to improve the elasticity with the present alloy.

Furthermore, a mixed medium may be used in special cases.

The binder referred to in the present invention includes organic compounds that share the above-mentioned functions and organic-inorganic complex compounds such as organic silicates and organic titanium interconnects.

Permanent magnets based on the present alloy system can be manufactured using conventional techniques such as heat treatment in a magnetic field after sintering and aging treatment. Of course, it is necessary to select and use an alloy powder having an appropriate particle shape and particle size distribution so as to obtain the highest possible sintered density after sintering. For that purpose, the amount of anthriazene is 2P - (xlD) (where A is the content below a certain particle size X, D is the maximum particle size present, m-17~l/
It is desirable to have a particle size distribution close to 3). The degreasing speed depends on the thickness of the molded body, the atmosphere, and the type of binder, but in the range from the temperature at which the binder starts to decompose or volatilize to the temperature at which it turns red, the degreasing speed is about 2 to 1 hour.
Approximately 0 C/h is suitable. If the degreasing rate, that is, the rate of temperature rise, is too rapid, bubbles, cracks, and cracks will occur on the surface and inside of the molded product.It will not be a quality product.The sintering temperature is generally 1200 to 1400C, but sintering should be done quickly. In order to proceed to a higher temperature and to improve the sintering density, sintering is carried out at 1300 to 1400 U&degree. Hereinafter, the present invention will be explained in detail with reference to Examples.

Example 1 At7, Ni15.0o30, qu4 in weight ft%
, Ti 5 , Nb0. Alloy powder of 100 mesh or less consisting of IVO, l remainder 78, HDPx, APP
(The blending ratio of the binder consisting of high molecular weight 1 and APP (low molecular weight) is powder: ) IDPEi; APP (polymer): APP (low molecular weight) = 98: 5: 9:
The mixture was heated and mixed at a ratio of 3 to 3, and a cylindrical molded body having a diameter of 20-10 tm was obtained using a screw type injection molding machine. Next, degreasing was carried out at a heating rate of 3 c/h from 140°C. Table 1 shows the ratio of degreasing to temperature. Then in vacuum 1100 U x 30 m1n + 1300 i;'
Sintering was performed for 2 hours.

Table 1 The degree of vacuum at this time was about 10-'torr or less.

Holding 1100CX for 30 min is due to O from the binder, which is thought to remain in a small amount in the powder, and O in the powder.
This is to promote and eliminate the reaction with 2. 2000 after sintering
In a magnetic field of 0θ, solution treatment was performed at 12501: followed by rapid cooling, followed by long-time aging treatment at 60017. The obtained magnetic properties are Br=7590G
Hc-13300e (BH)max-3,2MGO
It was e. Moreover, the dimensional accuracy for 40 samples was 0511111 or less for soil Q.

Example 2 An alloy powder of 100 mesh or less consisting of At18, N114.0024, Ou3, and the balance 7e in weight% was prepared in Example 1.
The magnetic properties of the magnetic material obtained by processing similar to B
r-12KG, I (c = 6000e, (BH)
It was max-5.0 MGOe.

Also, the dimensional accuracy for 4θ samples is ±0.
．． It was less than 5 attacks.

As is clear from the above examples, the material of the present invention has sinterability,
It is a magnetic material with poor dimensional accuracy and magnetic properties.

Claims (1)

[Claims] 1. In the alnico thread permanent magnet material, after mixing or kneading the powder made of the magnet material with a binder,
1. A permanent magnet material which is formed by injection molding, followed by debinding and sintering, and is made by injection molding using at least two types of organic materials. 2. At least two types of organic materials selected from among thermoplastic resins, thermosetting resins, natural resins, rubber, elastomers, lubricants, and plasticizers are added to the alnico thread magnet material powder, mixed or kneaded, and then injection molded. A method for producing a permanent magnet material according to item 1, in which: