JPS60100647A - Manufacture of alnico type sintered magnet alloy - Google Patents

Abstract

PURPOSE:To manufacture a sintered magnet alloy having desired magnetic characteristics when a sintered magnet alloy is manufactured from alnico alloy powder and a binder, by using a specified amount of camphor as the binder. CONSTITUTION:To 100pts.wt. alnico alloy powder consisting of prescribed percentages of Al, Co, Cu, Ti, Zr, Si, Mn and Fe is added 0.1-5pts.wt. camphor as a binder. They are mixed, filled into a metallic mold, and compression-molded under about 3-10ton/cm<2> pressure. The molded body is heated at about 100- 800 deg.C in vacuum or H2 to remove the binder, and it is sintered at about 1,200- 1,300 deg.C. The sintered body is subjected to soln. heat treatment, isothermal treatment in a magnetic field and aging to obtain a sintered magnet alloy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an alnico-based sintered magnet alloy using alnico yarn alloy powder as a starting material.

Magnet alloys containing At, R1, Oo or At, Ni with the remainder being substantially Fe (hereinafter referred to as Alnico magnet alloys) are typically of Alnico 1 to Alnico type.
8, etc., and are generally manufactured by melting and casting, but products with complex shapes and small items are also manufactured using powder metallurgy techniques.

By manufacturing Alnif thread magnet alloy using this powder metallurgy method, that is, the sintering method, it is possible to eliminate the complicated process from bath heating to solution treatment, or the extremely simple process of mixing raw material powder, molding, and sintering. Since there is no need for a pipe, the advantage is that the overall yield is particularly improved compared to the conventional melting and casting method.

As a method for producing alnico-based sintered magnet alloy, AL,
lii, Co, Ou, Ti or Tin2, FeTi,
A common method is to mix powders of each component element such as Fe or an alloy thereof so as to have a certain chemical composition, and then to perform molding, sintering, and inking. In this case, in order to prevent deterioration of magnetic properties due to oxidation, Fe is used instead of At.
-It is common to use At master alloy powder.

On the other hand, there is a method of forming, sintering, and heat-treating an alloy powder of a predetermined chemical composition as a raw material.

Conceivable. This method produces aluminum alloy powder.

Easily manufactured from runners etc. generated during casting of Co-based alloys.

Therefore, it is extremely effective in reducing manufacturing costs.

However, alnico alloy powder has extremely poor formability compared to powders obtained by mixing powders of each of the above-mentioned component elements or their alloys, so it is virtually impossible to form them alone.

For example, an Alnico 8 alloy with high 000 and T1 content has a Vickers hardness of Hv700 or higher and has almost no ductility, so it is relatively easy to grind it into powder, but it cannot be compression molded.

However, sufficient strength of the compact could not be obtained, making it difficult to use sintered magnets as synthetic fibers. Therefore, a method has been proposed in which powders of various component elements occurring above are blended with alnico alloy powder and used as raw material powder, but from the viewpoint of formability, the amount of blended alnico alloy powder is limited to approximately It had to be 60% by weight, and the effect of using the alnico alloy powder could not be fully exhibited. In addition, various binders are used to improve formability in the production of sintered magnets such as ferrite magnets, but no binder suitable for production of alnico-based sintered magnet alloys has yet been found. That was the reality.

An object of the present invention is to eliminate the drawbacks of the prior art described above, and to produce an alnico-based sintered magnet alloy having desired magnetic properties even when using raw material powder consisting essentially only of alnico-based alloy powder. The purpose is to provide a method.

The method for producing an alnico-based sintered magnet alloy of the present invention includes combining at least an alnico-based alloy powder and a binder, followed by pressure forming, sintering, and heat treatment. It is characterized by the fact that it was used.

The details of the present invention will be explained below in the order of steps.

First, in the present invention, an alnico alloy powder is prepared by pulverizing the return material obtained during casting of the runner, etc. described above using a pulverizer.

Next, a binder is added to and mixed with the above alnico alloy to obtain a raw material mixture. The inventors of the present invention (as a result of various studies on inders) have found that sufficient strength of the molded product can be obtained by using camphor. To be more specific, the binder for molding sintered magnets may be inorganic or organic/ There are various kinds of inders, but metal powders are not suitable as they change the composition of the magnet alloy.On the other hand, even organic inders can ultimately remain in the magnet alloy. A material with a large t is unfavorable in terms of magnetic properties. In short, it is desirable that the molding binder has a sufficient binder effect and leaves almost no residue after sintering. Moreover, since the compact is generally sintered after removing the binder (degreasing), in order to reduce carbonization, an organic compound that does not contain an O double bond in the structural formula, especially a benzene ring, An inder is preferred. As a result of various studies on organic binders that meet these conditions, camphor was found to be the most suitable. Camphor has a sufficient binder effect and has the property of sublimating over time. Furthermore, as it is clear from the structural formula below, camphor does not contain zero double bonds, so even after binder removal treatment, residual O and other residues are sufficiently reduced to the extent that they do not have a negative effect on magnetic properties. be able to. In addition, if the amount of camphor used is 100 parts by weight of alnico alloy powder, if the added amount is less than 0.1 parts by weight, it will not have the effect, while if it exceeds 5 parts by weight, there will be a lot of residual liquid and it will be used when magnetic.

This is because the quality decreases. When using camphor, dissolve it in an organic solvent such as alcohol first.

When mixed with Nico-based alloy powder, the alloy powder becomes camphor.

This makes it possible to reliably coat the product.

Extremely effective in improving oiliness.

°V“ The raw material mixture thus obtained is placed in a mold.

Fill with tomoe and compression mold. Molding pressure is 3 to 10 t':'
The range of 4@ is appropriate.

The desired molded body is heated to a temperature of 00°C for 100 minutes (
The binder is removed, preferably in vacuum or in H, and then sintered. Sintering is preferably carried out in vacuum or in H2, and the temperature is suitably in the range of 1200 to 1300 DEG C., depending on the viscosity of the alloy.

This sintered body is then subjected to heat treatment, specifically solution treatment, isothermal magnetic field treatment, and aging treatment to obtain an alnico-based sintered magnet alloy. Here, the heat treatment is solution treatment at 900-
Hold at a temperature of 1300 °C for 05-1 h, and perform isothermal magnetic field treatment at a temperature of 750-850 °C in a magnetic field of 2-5 KOe for 5 h.
After holding for ~30 minutes, cooling is performed, and aging treatment is performed for 5 minutes.
It is appropriate to carry out the aging at a temperature of 00 to 700[deg.] C. for 5 to 700 degrees Celsius (however, multi-stage aging may also be used).

The specific composition of the alnico alloy powder used in the present invention is, for example, 13 to 28 by weight and At6 to 1
5%, OoO~35%, OuO~6%, TiO~9
%, Zr O ~ 3%, Si O ~ 3%, Mn 1% or less, and the remainder substantially consists of Fe.

The effects of the present invention will be explained below using experimental examples and examples, but the scope of the present invention is not limited thereto.

Experimental example weight ratio ktB%, Ni15%, 0o35%,
Alnico alloy (casting material equivalent to Alnico 8) consisting of Ou & 5%, T15% 171) 0.5%, and the remainder substantially Fe
was coarsely crushed using a show crusher and finally wet crushed using an attritor to a particle size of 250 mesh or less.

The obtained pulverized powder was used as it was and molded under a pressure of 8t/α2 to obtain a molded body (sample &l) having an outer diameter of 115 mm and a long height.

In addition, 05 parts of camphor soaked in alcohol, 1 part of camphor, and 2 parts of camphor were added to 100 parts of the above-mentioned pulverized powder, and mixed thoroughly to form a raw material mixture. Molding was carried out under the same conditions as above to obtain molded bodies of type 38iI (sample points 2 to 4).

Table 1 shows the results of evaluating each of the above samples using the Rattler test (200).

Table 1 From Table 1, it can be seen that sufficient strength of the molded product can be obtained by adding 1 part or more of camphor.

Examples The molded bodies obtained in the experimental examples (Samples 1i 2 to 4) and the molded bodies (Sample A5.6) produced under the same conditions except that the amount of camphor added was 5 parts by weight and 6 parts by weight were used. The binder was removed by heating at a rate of 1.5°C/h to a temperature of 200°C in a vacuum, and then the binder was heated in a vacuum (10” torr) for 13 hours.
It was sintered by heating at 00°C for 3 hours. The sintered body was heated to 1250° C. for 1 hour to undergo solution treatment, then maintained at 830° C. for 1 hour in a 3KOe magnetic field, cooled and subjected to isothermal magnetic field treatment, and then subjected to multi-stage aging treatment.

The magnetic properties and residual C content of the obtained Alnico-based sintered magnet alloy and cast material (Alnico 8) are shown in Table 2. As is clear from Table 2, the amount of camphor added is 5. As long as the amount is less than 1, there is no problem with the residual C content, and the magnetic properties are almost the same as those of cast materials.

As described above, the present invention provides an alnico-based sintered magnet alloy that has desired magnetic properties even when substantially only alnico-based alloy powder is used as the raw material powder.

Obtainable.

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Claims (1)

[Claims]L A method for producing an alnico-based sintered magnet alloy, which comprises mixing at least an alnico thread alloy powder and a binder, and then performing pressure forming, sintering, and heat treatment, wherein camphor is used as the binder and the alnico-based alloy powder is mixed. A method for producing an alnico-based sintered magnet alloy, characterized in that α1 to 5 m parts are used for a part of 100 parts. 2. A method for producing an alnico-based sintered magnet alloy according to item 1 of the scope of the Patent Shima Momu, characterized in that camphor is bathed in an organic solvent and then mixed with the alnico thread alloy powder.