DE1956740B2 - Use of an alloy of samarium and cobalt as a permanent magnet material - Google Patents

Description

The invention consists in the use of an alloy of 34 to 42% samarium and cobalt as their percentage by weight between those of Sm ₂ Co ₇ and SmCo ₅ , which are ground and pressed in a magnetic field. SmCo ₅ contains approximately demagnetized, sintered and equal or less than 33.8 _{% samarium and Sm 2} Co ₇ approximately 42.2%. opposite direction compared to the first magnetization direction has been magnetized, as permanent 65 contain between about 37.5 and 40.5% samarium magnet material with a maximum energy pro- and correspond to a mixture of approximately glidukt of more than 9 X 10 ⁸ Gauss Oersted. the molecular fractions of SmCo ₅ and Sm ₂ Co ₇ .

Preferred is a use with the While the platinum-cobalt materials, the z. Currently as

Apply quality scale, maximum energy products of _e twa having 9 X 10 "gauss · oersted has a samarium cobalt in a weight percentage of 39-.Ό samarium a maximum energy product of more than 15 X 10 · gauss · oersted. Since materials made of samarium and cobalt have a significantly lower specific weight than platinum-cobalt materials, the ratio of magnet strength to mass exceeds that of z. Currently the best comparison materials by far. It can be seen from curves 14 and 15 ″ of the diagram that the permanent magnet materials according to the invention are clearly superior to _{those made of SmCo 5 alone.}

The following process for producing the inventive Permanent magnet materials has proven to be " proven to be particularly useful:

Samarium and cobalt are mixed in the desired ratio of e.g. 39 <Vo Samarium and 61% cobalt is filled in a container made of a material which does not react with either of the two elements greed. Such a material is e.g. alumina. The mixture of samarium and cobalt is used up to Melting point heated, for which about 1500 ° C is sufficient, and is kept in this liquid state for a few minutes in order to ensure that it is homogeneous To achieve mixture. This step is preferably carried out under a neutral atmosphere, such as a Eddgas, such as helium, executed. It has proven satisfactory to take this step with atmanschem To perform pressure. 3 »

The alloy melt is at room temperature cooled and then ground to a fine powder. The material is brittle and easy to grind. The marriage can continue in a silting-up area will. The samarium cobalt powder thus obtained becomes the desired one under high pressure Pressed shape. Satisfactory densification can be achieved at a pressure of around SMp / cm * although higher or lower pressures can be used. When pressing, in a magnetic field is applied in a predetermined direction, so that the particles are aligned on a preferred magnetic axis. A shaking of the powder however, during pressing the mechanical uniformity of the material also improves obtain satisfactory magnets without such shaking. The compact obtained is already a Permanent magnet.

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1 sheet of drawings

Claims (2)

Provided that with a composition of 37.5 patent claims: up to 40.5%> samarium and cobalt as the remainder, the maximum energy product is more than 15 X 10 "Gauss. 1. Use an alloy from 34 to sted. 42% samarium and cobalt as the remainder, which is milled Magnetic - the attached diagram, which has been magnetized for the direction of force, as see remanence and coercive force for a permanent permanent magnet material with a maximum 10 magnet white material according to the invention and for ver energy product of more than 9 X 10 ⁶ Gaussian different known permanent magnet materials -Oersted. gives. The diagram contains a curve 11 which represents the 2. Use according to claim 1 with the dimensional properties of platinum-cobalt, one for would be that with a composition of 37.5 ferrite magnetic materials characteristic curve 12 to 40.5% samarium and cobalt as the rest of the 15 and one for the class of the Alnico magnetic materials maximum energy product more than 15 X 10 ⁶ typical curve 13. The curve 14 illustrates the Gauss · Oersted is. same properties for a permanent magnet material according to the invention. In curve 15 are the the same properties for SmCo ₅ are shown. 20 The platinum-cobalt material is, for example, a benchmark for quality for permanent magnet materials. He owns There is a need in the art for permanent magnets - a very large coercive force of approximately 4000 materials with a high energy product. With the Ver Oersted, a remanence of around 6000 Gaussian reduction of electrical and electronic components and an energy content of approximately 9 X 10 ⁶ , this demand has increased by leaps and bounds. The need as Gauss · Oersted. Wherever there is a demand for a larger body in various areas of application, such as the ability of permanent magnet materials to be strong enough to justify the use of electronic equipment for the aerospace industry, such as equipment for aerospace, traveling wave tubes, motors and space travel, platinum-cobalt is actually used z. Currently gyroscopes, switches, hearing aids, and especially with ex- the preferred material. tremendously small electrical apparatus, such as electrical equipment Clocks, especially women's small clocks. Reasonable price available permanent magnet work .toff There are many types of permanent magnet materials, mainly ferrite magnet material properties are required, e.g. the coercive force is used, although this is much less favorable than the Pia temperature, the material strength and the like in terms of its suffering remanence, thermal stability, curie performance. affect. 35 tin-cobalt. So have Ferritmagnetwerkstoffe only under the assumption that for the other Eigenschaf- an energy content of up to 3.5 XLO ⁰ Gauss · oersted th the desired values are reached, is an extremely important when high permeability at low stability particularly valuable combination high REMA is sufficient, Alnico-9 (curve 13) is a very satisfactory product with a simultaneous high coercive force, so that permanent magnet material,
the product of these two quantities, the energy product. The invention relates to the fact that dukt is as large as possible. Alloy obtained with the help of a sintering process According to the "Journal of the Less-Common Metals", genes from cobalt and samarium, which from about 34 to 14 (1968), p. 323 to 328, the entire phase dia- 42% samarium and the rest consist of cobalt, gram of the samarium-cobalt system. not only have energy contents that those Here, too, there is a general reference to 45 surpassing the previous permanent magnet materials, advantageous magnetic properties on the inter- but also a high Curie temperature or high metallic compounds of rare earth metals - temperature resistance. It is about len with cobalt. thus about permanent magnet materials that are in proportion According to the "Journal of Applied Physics", 38 on their size and weight extremely lei- (1967), pp. 1001 and 1002, it is known that in a 5 ° are powerful and even the properties of the pia magnetic field of some Outperform Kilo-Oersted in various tin-cobalt materials. They are _{inexpensive enough of compacted SmCo 5} powder binders to enable their application in competitive products with a remanence of 5100 Gauss, a coercive force of commercial products, and sufficient of 3200 Oersteds and a maximum energy product powerful to produce improved results in 5.1X 10 * Gauss · Oersted. 55 application requiring the highest The object of the invention is to offer a permanent magnet, like that of the modern one material of the samarium-cobalt system with still electronic technology in which the ratio of significantly higher maximum energy product - power to size or power to weight ben. is crucial.