DE1083742B - Process for the production of ferromagnetic materials with a gyromagnetic effect - Google Patents

Description

GERMAN

The invention relates to a method of making ferromagnetic materials for use are determined in facilities which the geomagnetic effect in the field of waveguide technology (Waveguide technology), i.e. in the high frequency range.

These devices can, in particular, be switches, phase shifters, modulators, switches or isolating devices be for electromagnetic waves, d. H. Bodies that have different attenuations for the Transmission of electrical waves in the two transmission directions, without relying on the above Enumeration to be limited.

The properties of the materials are given below for the case of a device using the Faraday effect indicated in which the ferrite is in the form of a cylindrical rod of circular cross-section is used, which is arranged in the axis of a circular waveguide and a permanent longitudinal magnetic field is subject. One connected to the input of the apparatus by a transition connection rectangular waveguide introduces a linearly polarized wave into it. The passage through the gyromagnetic Medium causes a rotation of the plane of polarization. The outgoing wave goes through mediation a second transition connection into a rectangular waveguide, the cross-section of which is oriented so that a maximum of power is transmitted. A "transition connection" is a waveguide from a Understood geometric shape, which is used to connect the central circular waveguide with the outer rectangular waveguides.

Given the dimensions, the gyromagnetic means is determined by that produced by it Angle of rotation of the plane of polarization, the attenuation of the wave passing through it, expressed in decibels (db) by the logarithm of the ratio of the greatest incoming power to the greatest outgoing power, and the ellipticity of the outgoing wave, expressed in db by the logarithm of the ratio of the largest to smallest power that is obtained when twisting the rectangular output conductor around its axis. The ferrites produced by the process according to the invention result in all of the above-listed devices very little attenuation in the normal transmission direction and in those using the Faraday effect Facilities a sufficiently large angle of rotation and a very good ellipticity, i.e., the exiting Wave is almost linearly polarized. In addition, they only require a very weak magnetic field for their application.

The method relates in particular to the production of such materials on the basis of Ni-Zn ferrite. Ni-Zn ferrites are already known per se. The specified

Method of manufacture
ferromagnetic materials
with gyromagnetic effect

Applicant:

Center National

de la Recherche Scientifique,

Paris

Representative: Dipl.-Ing. B. Wehr, Dipl.-Ing. H. Seiler,

Berlin-Grunewald,

and Dipl.-Ing. H. Stehmann,

Nuremberg 2, Essenweinstr. 4-6, patent attorneys

Claimed priority:
France from May 2, 1956

Charles Louis Guülaud and Roger Vautier,

Bellevue, Seine-et-Oise (France),

have been named as inventors

however, favorable properties are only achieved through the manufacturing process. This is characterized in that a powdery mixture of 30 to 50 mol percent Fe ₂ O ₃ , 13 to 20 mol percent NiO, 2 to 20 mol percent (preferably 5 to 15 mol percent) Cr ₂ O ₃ , remainder ZnO is deformed by pressing and the body obtained be fired at 1150 to 1350 ⁰ C in an oxidizing atmosphere.

Advantageously, the sum of the mole percentages is the ferric oxide (Fe ₂ O ₃₎ and the chromic (Cr ₂ O ₃₎ 46-54 ° / _0th

The heat treatment is preferably carried out at temperatures between 1150 and 1350 ° C. the Oxidizing atmosphere can consist of pure oxygen or a mixture of oxygen and neutral Consist of gas, e.g. B. from air, but in general there is as great an oxygen content as possible in this atmosphere useful to reduce the losses in the gyromagnetic mean.

This process enables a material with an attenuation of less than 0.5 db to be obtained transmitted electromagnetic wave, the shaft rotation satisfying the application conditions.

In the foregoing, for the sake of simplicity, when specifying the molar percentages, it was assumed that the metals in the starting mixture were only in the form of ferric oxide (Fe ₂ O ₃ ), nickel oxide (NiO), chromium oxide (Cr ₂ O ₃ )

009 530/478

Claims (1)

3 4 and zinc oxide (ZnO) are included. These metals Example IV but can just as well be present in another form, the following mixture is in the specified molecular z. B. ground in the form of other oxides or salts and large percentage ratios: NiO 17%, Cr ₂ O ₃ also in metallic form; in these cases it is sufficient to add 7%, Fe ₂ O ₃ 44%, ZnO 32%. After compression molding these latter actually present oxides, salts or 5 and sintering at a temperature of 1220 ° C during This brings metals into the above-mentioned oxides with the same 4 hours under an oxygen atmosphere Number of metal atoms in the usual way to convert material in the form of a round rod of 5.5 mm and for the latter the conditions given above diameter and 30 mm length at a frequency of to be observed. 9700 MHz a rotation of 30 ° and a negligible-Im The following is intended to provide a better understanding of the attenuation that can be achieved when there is a longitudinal magnetic field Finding a number of working examples to be exposed by 100 Örsted.
Invention specified without this being limited thereto should be. Example V Example I. 15 The following mixture in mol percent: NiO 17%, Cr ₂ O ₃ In a ball mill charged with iron balls, 7%, Fe ₂ O ₃ 44%, Zn O 32%, is ground and a mixture of the following ingredients is pressed for 24 hours. It is then sintered for 4 hours at 1200 ° C. in the specified molecular percentage ratios in an oxygen atmosphere. Ground in the form of a round: NiO18%, Cr ₂ O ₃ 10%, Fe ₂ O ₃ 41%, ZnO31%. Rods 6.5mm in diameter and 30mm in length The product is sintered after compression molding at a temperature of 20, when exposed to a longitudinal magnetic field temperature of 1250 ° C for 4 hours in Sauer- von 100 Örsted, a rotation of 90 ° material atmosphere and then for 16 hours and an attenuation of 0.3 db emerges,
cooled in the same atmosphere. One such. Material in the form of a round rod from Example V 5.5 mm in diameter and 30 mm in length is used, 25 A mixture of the following components causes a rotation of the specified molecular percentage ratios of the polarization plane of 30 ° at the frequency of 9700 MHz when it is ground: NiO 13 %, Cr ₂ O ₃ 5%, Fe ₂ O ₃ 49%, ZnO 33%. Longitudinal magnetic field of 100 Örsted is exposed. The This product is after compression molding with a wave damping is 0.04 db. The ellipticity of the out-temperature of 1250 ° C. for 4 hours under acid-treading wave is sintered in the manner explained above and then cooled. One measured - about 30 db. such material in the form of a round rod of In comparison, a material produced and used under the same conditions, 5.3 mm in diameter and 30 mm in length, but with a frequency of 9700 MHz, produces a rotation of the polarization-following composition in mole percent, the plane of 50 ° if it is exposed to a longitudinal magnetic field of chromium oxide (Cr ₂ O ₃ ) by an equivalent amount of 35 out of 100 Örsted. The shaft damping is replaced by ferric oxide: NiO 18%, Fe ₂ O ₃ 51%, ZnO 0.17 db. The ellipticity of the exiting wave is 31%, a rotation of 68 ° and an attenuation of - measured as explained - over 35 db.
0.7 db, the ellipticity of the exiting _. . _{,, rTT} WeUe is equal to 7 db. Example VII Example II ⁴ ° ^ ^s ™ ^{1 <} ^ ^ ^as f ° lg ^{en (} le mixture in the given ground molecular percentages: NiO 20%, It is a mixture of the following components in Cr ₂ O ₃ 20%, Fe ₂ O ₃ 30%, ZnO 30%. This product is ground to the specified molecular percentages after compression molding at a temperature of 1250 ° C: Ni O 18%, Cr ₂ O ₃ 10%, Fe ₂ O ₃ 40%, Zn O 32%. sintered for 4 hours under an oxygen atmosphere. After compression molding, this product is sintered in a substance atmosphere and then cooled down in the form of a round rod at a temperature of 1250 ° C. for 4 hours under Sauer - 6.5 mm in diameter and 30 mm in length. A frequency of 9700 MHz causes a rotation of the polarization of such material in the form of a round rod of plane of 25 ° when it is subjected to a longitudinal magnetic field of 6 mm diameter and 30 mm length when the Fre-100 Örsted is subjected. The wave attenuation is a rate of 9700 MHz a rotation of 48 °, if 50 0.09 db. The ellipticity of the exiting waves is about. it exposed to a longitudinal magnetic field equal to 100 Örsted 35 db.
will. The wave attenuation is 0.08 db. _ In comparison, a result under the same conditions = materials produced and used, but the 1st process for the production of ferromagnetic materials has the following composition in mole percent, where 55 - materials with a gyromagnetic effect based on chromium oxide (Cr ₂ O ₃ ) by an equivalent amount of Ni-Zn ferrite, characterized in that a pul- Ferrioxyd (Fe ₂ O ₃ ) is replaced: NiO 18%, Fe ₂ O ₃ 50%, deformable mixture of 30 to 50 mol percent Fe ₂ O ₃ , ZnO 32%, a rotation of 70 ° and a damping 13 to 20 mol percent NiO, 2 to 20 mol percent (before- of 0.8 db. . 'preferably 5 to 15 mol percent) Cr ₂ O ₃ , remainder ZnO .Example 111 _6o deformed by pressing and the bodies obtained It is the following mixture in the specified at 1150 to 1350 ° C in an oxidizing atmosphere. . Molecular percentage ratios ground: NiO 18%, to be burned. Cr ₂ O ₃ 15%, Fe ₂ O ₃ 35%, ZnO 32%. This product 2. Method according to claim 1, characterized in that is drawn after compression molding at a temperature of that the sum of the mole percent of iron 1200 ° C for 4 hours in an oxygen atmosphere sinters 65 oxide (Fe ₂ O ₃ ) and chromium oxide (Cr ₂ O ₃ ) between 46. This material is in the form of a round stick and 54% is 5.5 mm in diameter and 30 mm in length of the frequency of 9700 MHz a rotation of 45 ° in the publications considered: an attenuation of 0.05 db, according to "The Bell System Technical journal", 1952, in particular Longitudinal magnetic field equal to 100 Örsted is subjected. 70 p. 23.