DE1958280A1 - Process for the production of permanent magnets - Google Patents

Description

Public limited company Brown Boveri & Cie., Baden

Process for the production of permanent magnets

The present invention provides a method of manufacture of permanent magnets, especially fine particle magnets of intermetallic compounds consisting of at least one 3d transition element with one or more rare ones Earth metals.

For the production of permanent magnets, especially fine particle magnets are intermetallic compounds of binary systems of a 3d transition element with a rare earth metal element

5o7 - case 1 / F / k

009886/1281

known. Preferably binary compounds of the group RgCo-j ^ and RCo ^ with the rare earth metals Y, La, Ce, Pr, Nd or Sm for use. Peinpartikelraagnete in the order of magnitude of microns became melt metallurgical by grinding manufactured blanks made from an intermetallic compound.

I.

This method has the disadvantage that the magnetic properties of the binary compounds 3d transition element / rare earth are changed unfavorably during the grinding process. Up to a particle size of Io to 15 J * , the coercive force increases and decreases when the grinding process is started. This deterioration in the magnetic properties is called excessive defects.

. Purpose of the present invention is to provide a process for the preparation of Daueruagenten, particularly Pein- W particle magnets in which the Uebermahlungseffekt is avoided.

According to the invention, this object is achieved in that in A rare earth metal hydride powder with a protective atmosphere , a purified 3d metal powder in a stoichiometric ratio blended, pressed into a blank and then with the exclusion of nitrogen, oxygen and carbon at 75o to 125o ° C is sintered for four to ten hours.

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The method according to the invention makes it easy to disintegrate Obtained sintered body that does not require significant grinding. Another advantage is that the sintering temperature reads far below the melting temperature of the components. As a result, there is no reaction with the crucible material a, was. results in a much cleaner and better material. The rare earth metal hydride can be produced by the glowing of Oxide and nitride layers of purified rare lrum metals in the Vacuum at 600 C with. subsequent passage of hydrogen at 300 ° C up to the Latti ^ umr are formed.

The cleaning of the rare earth metal from oxide and nitride layers can be done mechanically in an inert nitrogen stream.

It is preferably provided that the hydrogen is passed over takes place for at least one hour.

After the rare earth metal has been converted into the hydride form, it can be ground in a protective argon atmosphere.

The 3d metal is preferably mixed as a cchwanua ax with the rare earth metal hydriapowder and ^{pressed under a pressure of 2oo κρ / cm 2} to form a blank.

Cobalt is preferably used as the 3d metal.

Sintering can take place in a vacuum or under a protective gas atmosphere

009886/1281

BAD © RIGINAL

example 1

a) Production of Sm hydride

·. A bare piece mechanically cleaned under a stream of nitrogen Samarium metal (1.0 g) was annealed in vacuo at 600 ° C for 3 hours, to add oxygen and nitrogen added to the surface remove. In the same apparatus, well-tormented hydrogen is poured over the metal piece at 300 ° C. until it is complete ^ Saturation transferred. The reaction took about 2 hours. It creates SmH, which is stored under hydrogen gas,

b) Production of Co, -Sm

The samarium hydride is ground to about f- size in a cuticle box filled with argon and mechanically mixed well with cobalt sponge.

Initial weight : 1,000 g Sm 1,960 g Co Pressing pressure : 200 kgf / cm ² . Tablet diameter : 13 mm Sintering temperature : 950 ° C Sintering time : Io hours vacuum : 2.10- ⁶ Torr

X-ray crystallographically, the compound produced was identified as identified.

Part of the sintered tablet was powdered by mechanical shattering without grinding and examined in the magnetometer. the measured coercive field strength was 3000. Oe.

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Example 2

a) Production of Y-hydride

A bare piece of yttrium metal (4.0 g) mechanically cleaned under a stream of nitrogen was in vacuo at 600 ° C for 4 hours annealed. Then, well purified hydrogen was passed over the metal at 400 ° C. until it was completely saturated. The reaction time was 8 hours. X-ray crystallograchically the reaction product "was identified as YH. The Aufber The hydride was maintained in a Schuff vessel under water off gas.

b) Production of Co ₁ -Y * - = - ■■ -

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In an argon-filled Kuppelbox the Yttriumhydrid was alen on Mi -Large Geml ^ and well blended mechanically with cobalt sponge.

Weight: 4.0OgY

"13.10 g Co

Compression pressure: 2oo kp / cm ^ tablet diameter: 13 now

Several tablets 8-10 mm in height were produced.

Sintering temperature: 1180 ° C. sintering time: 8 hours vacuum; lo ~ ⁴ torr

The intermetallic compound produced could be identified _{as Co 5 Y by X-ray crystallography.} Powder produced by mechanical shattering gave a coercive field strength of 165o Oe ₀₀₉ S 8 6/1 2 8 1

Example 3

a) Production of Sm hydride

The samarium metal (12 g), mechanically cleaned in a stream of nitrogen, was annealed in vacuo at 600 ° C. for 5 hours. Afterwards Purified hydrogen is passed over the metal at 300 ° C until it is completely saturated. The response time was 5 hours. The reaction product was X-ray crystallographic identified as SmHo. The · SmH-. was in a ground joint vessel stored under hydrogen gas.

b) Production of Co ₁ -Sm

In a dome box filled with argon, the samarium hydride was ground to a size of yu and mixed with a cobalt sponge.

Weight: 12.00 g Sm

23.51 g of Co

Compression pressure: 200 kp / cm ² tablet diameter: 13 mm

Production of several 6-7 mm high sintered tablets

Sintering temperature: 980 ° C. Sintering time: 5 hours Vacuum: 2.10 torr

The intermetallic compound produced was identified by X-ray crystallography as Co ₅ Sm.

f Powder made by mechanical crushing gave the

Coercive field strength of 7500-8000 Oe.

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Claims (1)

- 7 - 50/69-uk Claims .1. Process for the production of permanent magnets, in particular fine particle magnets from intermetallic compounds consisting of at least one 3d transition element and one or more rare earth metals * characterized in that rare earth metal hydride powder purified in a protective gas atmosphere is mixed with purified ^ metal powder in a stoichiometric ratio to form a blank and then sintering with the exclusion of nitrogen, oxygen and carbon at 750 ° C to 1,250 ° C for four to ten hours. 2. The method according to claim 1, characterized in that a Jd transition element mixed with a rare earth metal will. 3. The method according to claim 1, characterized in that the rare earth metal hydride by annealing of the oxide and Nitrydschlchten purified rare earth metal in a vacuum at 600 ° C with subsequent passage of hydrogen is formed at 300 ° C to saturation. H. Method according to claim 3 »characterized in that the cleaning of oxide and nitride layers takes place mechanically in an inert nitrogen stream. 009886/1281 - 8- 50/69 5. The method according to claim 3, characterized in »that the hydrogen is passed over for at least one hour. 6. The method according to claim 4, characterized in that the rare earth metal hydride under an argon protective atmosphere is ground. 7 «Method according to claim 1, characterized in that the rare earth metal is Y, La, Ce, Cr, Nd or Sm. 8 · * Method according to claim 1, characterized in that the 3d metal is mixed as a sponge with the rare earth metal hydride powder. 9. The method of claim 1 or 8, characterized dase, the 3d metal cobalt. 10. The method according to claim 1, characterized in that the sintering takes place in a vacuum or under a protective gas atmosphere. 11. The method according to claim 1, characterized in that the mixed powder is pressed with a pressure of 200 kp / cm su a blank. Public company Brown, Boveri & CIe. 009886/1281