DE1104126B - Process for the production of magnetically anisotropic permanent magnets containing Ni, Al and Co as the main elements on an iron basis by casting - Google Patents

Description

GERMAN

The invention relates to a process for the production of magnetically anisotropic iron-based permanent magnets containing Ni, Al and Co as the main elements, the crystals of which are predominantly oriented so that the (100) direction is practically parallel to the preferred magnetic direction in which the magnet is magnetized is to be, and during the solidification of the alloy the part lying between the two pole faces of the magnet is surrounded by <4n material with exothermic combustion, for example on an aluminothermic basis (with temperatures of at least 1400 to 1500 ⁰ C occur), the heat of solidification in is derived in one direction or in two opposite directions.

Such a method is known and aims to reduce the heat dissipation between the two ends as much as possible to delay. According to this process, the material is exothermic combustion by the liquid alloy- self-ignited, which poured into the space surrounding by the mentioned material will. A disadvantage of this method, however, is that, because this inflammation is relatively long Time (for example, 20 to 30 seconds) required, the alloy is usually already solidified before the The material mentioned has assumed the maximum temperature, which results in the most favorable structure and thus the associated optimal magnetic properties cannot be achieved.

According to the invention, this disadvantage can be avoided by using metal or a metal alloy is poured into a space surrounding the mentioned material, causing this material to ignite and the magnetic stabilization only then, possibly through a separate feed channel through, is poured into the actual mold. The mentioned material is thus already on immediately the outside inflamed. In this way, a maximum time delay can be achieved.

According to a further embodiment of the invention, the mentioned space is made with the magnetic steel alloy fully poured myself, whereupon when pouring this alloy over the edge of the material runs into the actual mold until it is filled. The resulting time delay is sufficient often for practice.

According to another embodiment, openings through which are in the surrounding material the alloy can already run into the actual casting mold before the aforementioned surrounding space is filled, whereby the time delay is smaller if desired.

By finding the right compromise for a certain type of magnet, it is possible to achieve this Method of manufacturing magnetic

anisotropic, Ni, Al and Co as the main

permanent magnets containing elements

iron-based by casting

Applicant:

NV Philips' Gloeilampenfabrieken,
Eindhoven (Netherlands)

Representative: Dr. rer. nat. P. Roßbach, patent attorney,
Hamburg 1, Mönckebergstr. 7th

Claimed priority:
Netherlands 17 December 1952

Adolf Johannes Jacobus Koch,

Eduard Maria Henricus Lips

and Krijn Jacobus de Vos, Eindhoven (Netherlands),
have been named as inventors

that the moment approaches the maximum combustion temperature of the material mentioned coincides with the solidification moment (solidification range) of the magnet alloy.

By changing the size, number and location of the openings mentioned, practically any achieve any time delay smaller than the largest time delays. The invention is explained in more detail below with reference to a drawing in which an exemplary embodiment is shown schematically is shown.

In the figure, 1 denotes a metal cooling plate, 2 a ring made of a material with exothermic Combustion on an aluminothermic basis and 3 the rest, for example from molding sand existing part of the mold. It is poured into the space 4 surrounding the ring 2 (see arrow) until it is filled, whereupon the liquid alloy over the upper edge of the ring into the actual mold space 5 is running.

If 2 holes are made in the ring, for example as indicated by the dashed line 6, it is achieved that the mold space begins to fill up at an earlier point in time. Of course When determining the desired time delay, the dimensions of the

109 539/480

Ring 2 a role. Furthermore, the ring can be provided with a cover made of the same material be, wherein this cover can form a whole with the ring. The lid can contain openings for the escape of gases and vapors and / or the pouring opening.

In the case of an alloy consisting of 24% Co, 14% Ni, 8% Al, 3% Cu and the remainder Fe, a (BH ) _max achieved of 6V2 · 10 °, while according to the method according to the invention a (BH) _max of 7V2 · 10 ⁶ with an Hc of 725 Örsted and a Br of 14000 Gauss was achieved.

Claims (3)

PATENT KITCHEN: 1. A process for the production of magnetically anisotropic permanent magnets based on iron, containing Ni, Al and Co as the main elements, the crystals of the magnet being predominantly oriented so that the (100) direction is practically parallel to the preferred magnetic direction in which the magnet is to be magnetized , and wherein during the solidification of the alloy the part lying between the two pole faces of the magnet is surrounded by a material with exothermic combustion, for example on an aluminothermic basis, the solidification heat being dissipated in one direction or in two opposite directions, characterized in that, that a liquid metal or a metal alloy is poured into a space surrounding the material mentioned, whereby this ignites and the magnetic steel alloy is only then poured into the actual mold space. 2. The method according to claim 1, characterized in that the space with the magnetic steel alloy itself is fully poured, after which, with further pouring, this alloy over the edge of the material runs into the actual casting mold until it is filled. 3. The method according to claim 2, characterized in that openings are provided in the material are through which the magnetic steel alloy is already in the actual casting mold can run before the mentioned surrounding space is filled. Considered publications:
British Patent No. 661 727. 1 sheet of drawings © 109 539/490 3.