DE1414904A1 - Magnetically and crystallographically anisotropically sintered permanent magnet and process for its manufacture - Google Patents

Description

Magnetically and crystallographically anisotropically sintered permanent magnet and process for its production. It is known to manufacture magnets from alloys which, in addition to iron, essentially contain cobalt (15-30 #,), nickel (11 "5-20, j, x) and aluminum (6-11%) (Alnico magnets) These elements can contain 4. Uch, Ti (0-6%) e Cu (0-7 £ / j) t V, Nb and impurities together, individually or in combinations. These magnets can be roughly divided into four large groups: a) Alnico-.7l-dagneteg whose magnetic properties are the same in all spatial directions (isotropic Alnico-Iiiagnete) t which achieve a magnetic quality of approx. (BH) max = 2 - 106 G - Oa.

b) Alnico-1, magneteg in which a spatial direction is magnetically distinguished by a suitable heat treatment in 1, -magnetic field (anisotropic Alnio o magnets); with them one achieves magnetic quality values up to approx. (BH) Max = 595 - 10 6 G - Oe. measured in the marked direction (preferred direction) oo) Alnico4, magnets, which initially receive a crystallographic preferred direction, so that the predominant part of the existing crystallites are parallel with one of their (100) directions each (columnar crystallization) and which are then subjected to heat treatment is connected in the magnetic field, whereby the magnetic and crystallographic preferred directions coincide. Here we can. 6 values of the magnetic quality up to (BH) max m 9 10 G - Oe can be achieved.

d) Alnico-i..lagnetag which consist of a single crystal and in which the magnetic preferential direction of a (10C # orientation of the crystal is parallel, magnetic quality values of 12 - 1 G'- 08 have been measured on such crystals group a, b and o are already technically in large amounts hergestelltg the group d so far only in laboratory scale. Kiagnete of the groups A and B are both produced foot and eintertechnisch. te Leiagae-group a corresponding date been prepared by casting, as The columnar crystallization in the magnets of this group is forced by generating as strong a temperature gradient as possible during solidification from the melt.

Group d magnets have so far only been able to be pulled out of the melt with special precautionary measures.

In the method according to this invention, the stem crystals. This crystallographic preferential direction can be enforced by the following rules: -.- Eitv-ig, prepared according to known methods, an already finished ainico single crystal is added when it is poured into the mold, which has been obtained otherwise, for example by smashing a coarse crystalline casting. 100) direction of the ta ti Gi-crystal with the later crystallographic preferred orientation (stem axis) match. It can also been used some solohe Xristallite, but then on to "ensure that mindestoliß one of the (100) directions each! Crict # -lli lies parallel to the later stem axis, the sintering takes place at a slightly higher temperature than in the process known from the prior art and / or for a little longer. The range from 1330 to 135000 and Ging duration of 2 to 5 hours, especially a treatment of 4 hours at 1350 ° C., proved to be favorable Stengal axis worked, a magnetic quality of (BH) M 7-94 * 10 6 CT Max could be measured in the preferred direction.

b) To the mixture of metal powders to be pressed, which has been prepared in terms of composition and preparation according to methods known per se, already finished Alnico powder is added, because by grinding Äi.nico-mir.i, ag.neten, which are in the magnetically high quality Condition was established. The grain size of these Alnico powder particles must therefore be chosen so that each powder particle is a single crystal. The 1 inge of the added alnico powder can contain 0.5-50% of the metal powder. Mix, preferably 1-1Vio, during or after filling A magnetic field is perpendicular to the Preasmatrize - # u: r pressing direction of 100-10,000 Oe, preferably 500-3,000 Oe. The sintering and further treatment are carried out in an inherently b.ekp'nnter manner, with the temperatures and times mentioned under a) advantageously being used for the sintering and in the heat treatment lm "##, the field direction of the applied lagnetfeld to Riohtung before pressing Feldee must be parallel. On magnets made in this way. 1.9 were 6 goods values measured in the preferred direction of (BH) ... = 795 0 10 G - OB * a) The mixture of metal powders to be processed is prepared in one of the essential alloy constituents or copper or titanium with a deficit compared to the normal composition . The amount of this fahlendz Bestandtellas is In Draht.-41'orm in the Presa-1, gatrize introduced, wherein the Drähtg # nug "" allowed to run in parallel from a Begrenzuag, perpendicular to these limitations gegeau .6 - must be evenly spaced and should have from each other.

The wire axes are parallel to the direction of the desired column crystallization (column axes). The diameter of the wires can be between 0.01 and 1 mm, preferably between 0.05 and 0.2 mm. The direction of tear must be perpendicular to the wire axes. The sintering process is carried out as described under a), and the further treatment is carried out analogously to the processes known per se. Magnetic quality values (BH) 6 0% max 10 G - Oe can be measured on sintered magnets manufactured using this process.

d) Several mixtures of the metal powders are produced, which differ i by the content of one of the powders of the essential alloy metals. The concentrations of the mixtures at the chosen -e p (#. &, -_ ierungaffotall should not deviate too far from the magnetically optimal composition Prepare powder mixtures with 20, 2le 229 239 24, 259 26t 279. 289 # qo * These powder mixtures are introduced into the Preaoferm one after the other so that an even concentration gradient is created with 1/50 to 1 / 10- which is usually fixed in printing before the mixture is layered over it with the adjacent concentration a concentration gradient takes place in a manner known per se and in accordance with the method described under ao * The magnetic field is again pa during the heat treatment rallel to Stengelachseo to the executed example were found in 6 preferential direction magnetic quality values of 796 10 G o Oa * The under B to D described method allow to Er-.zeugung a curved Stengelkristallieptions by Is b in .Falle necessary the aligning magnetic field has a Curvature to gebOnp which corresponds to the later curvature of the stem axes * In the case of o the wires have to be bent in the direction of the desired stem crystallization, but care must be taken that the distances between the wires remain constant. In case d , the concentration case must have a curvature corresponding to the intended curvature of the stem axes *

Claims (1)

Claims Geainterterg magnetically anisotropic permanent magnet made of an alloy of iron with essentially cobalt, nickel and aluminum, characterized gekennzeichneti that it to the direction of the magnetic Vorzugelage contains paraUel a crystallographic preferred orientation, in which the crystallites of the permanent magnet body or a part of you with their (100 ) Directions are parallel to it. 2.) Geainterter permanent magnet nach'Anspruch 1, characterized in that it, as usual for this group of alloys, besides iron 15-30% cobalt, 11.5-20 % nickel and 6-11% aluminum and also 0-8% Copper, 0-6% titanium and optionally other additives together, individually or in combinations of some of them. 3.) A method for the production of sintered permanent magnets according to claims 1 and 2, characterized in that the mixture of metal powder when pouring into the mold, a finished Alnico single crystal is added so that one of its (100) directions with the desired Preferred direction coincides. 4.) Process for the production of sintered permanent magnets according to claims 1 and 2, characterized in that the mixture of metal powder 0.5-50 %, preferably 1-10% powder is added, which consists of a magnet of the same or similar composition, the Has been treated in such a way that it was in a magnetically high-quality state, was obtained, and the grain size of which is selected so that the individual grains are single crystals, and that further this mixture with its addition in the ireso form before a pressure is applied to a magnetic field exposure is from 100-10,000 Oe, preferably 500-3,000 Oe, the direction of this magnetic field coinciding with the direction of the magnetic field during the subsequent heat treatment and thus with the magnetic pre-layer. 5.) Process for the production of sintered permanent magnets according to claims 1 and 21, characterized in that the mixture of the metal powder is processed with a deficit of one of the alloy, spartner cobalt, nickel, aluminum or copper and the resulting amount of Pehl as Wire of 0.01-1 mm, preferably 0.05-0.2 mm in diameter, is injected into the mold in such a way that the wire axes are parallel to the required preferred magnetic position, perpendicular to the C: # boundary surfaces and stand at the same distance from each other. 6.) Process for the production of sintered DuLierm, - igneten according to claims 1 and 2, characterized in that dr-, r Irescl-illt --- is built up from several layers, whose metal powder mixture is s stepwise in the concentration of a ' of the alloying elements cobalt, nickel or aluminum in such a way that a concentration gradient with respect to the selected alloying element arises in the pressed part with an average concentration corresponding to a composition known per se. 7.) Sintered permanent magnet according to claims 1 and 2, characterized in that the crystallographic (, iiid T. # - j # -net, 1.sche) Vorzu - srIchtung. is curved inside the magnet. 8.) Process for the production of sintered permanent magnet ## r1 the CD claims 1, 2, 7 and 4, characterized in that d - s% .- ugnet 'field in the space of the, press mold a curvature corresponding to the desired curvature of the preferred position owns. 9.) Process for the production of sintered D-, uermc-ir - neto.n according to claims 1, 2-, 7 and 5, thereby g.eker .--- eichnet that the wire axes have one of the desired curvature of the preferred position obtain appropriate curvature. 0.) Process for the production of sintered De) uermag.net (-n according to claims 1, 2, 7 and 6, characterized in that the concentration gradient receives a curvature corresponding to the desired curvature of the preferred position.