SE184487C1

SE184487C1 -

Info

Publication number: SE184487C1
Authority: SE
Publication date: 1963-01-01

Description

Uppfinnare: E W Gorier Prioritet begtird [ran den 24 jannari 1956 (Nederlanderna) Det är f6rut kant, att foreningen BaFe12019 har permanentmagnetiska egenskaper. Denna forening karakteriseras av en hexagonal kristallstruktur (se J. J. Went, G. W. Rathenau, E. W. Gorter och G. W. van Oosterhout, Philips Technische Rundschau, 13, s. 361-376 (1952). Inventor: E W Gorier Priority begtird [January 24, 1956 (The Netherlands) It is a foregone conclusion that the BaFe12019 association has permanent magnetic properties. This compound is characterized by a hexagonal crystal structure (see J. J. Went, G. W. Rathenau, E. W. Gorter, and G. W. van Oosterhout, Philips Technische Rundschau, 13, pp. 361-376 (1952).

Enligt uppfinningen har det visat sig, att genom substitution av jarnjoner med andra joner en klass av nya foreningar kunna uppnas, vars blandkristaller skilja sig frail foreningen BaFeir On darigenom, att darav bestaende kroppar, och aven vid frekvenser pa 50 MHz och ofta vasentligt hogre, uppvisa begynnelsepermeabilitetsvarden som aro hogre och ofta avsevart hogre an 2, varigenom dessa foreningar bland annat aro lampliga att anvandas som material for magnetkarnor vid frekvenser Over 50 MHz. Namnda nya fOreningar ha en kristallstruktur, som ar densamma som den hos fOreningen BaFe12019 och kunna betraktas som harledda ur denim genom att i den angivna formeln en del av Fem-jonerna ersattas med en kombination av lika mangder Co'- och Tilv-joner. De nya fordelningarna kunna tecknas medelst formeln BaCouTirvFeur 019 a a (12-2a) 29 varvid a ligger mellan granserna 1,0 och 1,6 och foretradesvis mellan granserna 1,2 och 1,45 och varvid Ba-jonen helt eller delvis ersatts med en Sr-jon, en Pb-jon och/eller till hogst 40 atomprocent med en Ca-jon. According to the invention it has been found that by substituting iron ions with other ions a class of new compounds can be obtained, the mixed crystals of which differ from the BaFeir On compound in that existing bodies, and even at frequencies of 50 MHz and often substantially higher, exhibit initial permeability values that are higher and often significantly higher than 2, whereby these compounds are, among other things, suitable for use as materials for magnetic cores at frequencies above 50 MHz. Said new compounds have a crystal structure which is the same as that of the compound BaFe12019 and can be considered as derived from denim by replacing in the given formula some of the Fem ions with a combination of equal amounts of Co 'and Tilv ions. The new distributions can be drawn by the formula BaCouTirvFeur 019 aa (12-2a) 29 wherein a lies between the boundaries 1.0 and 1.6 and preferably between the boundaries 1.2 and 1.45 and whereby the Ba ion is completely or partially replaced by a Sr ion, a Pb ion and / or up to a maximum of 40 atomic percent with a Ca ion.

Framstallningen av materialen enligt uppfinningen kan ske genom upphettning (sintring) i syre eller luft av en i ratt forhallande vald, finfordelad blandning av de metalloxider av de nya foreningarna som skola sammansattas, vid en temperatur Over 1200° C. Darvid kunna naturligtvis en eller flera av de metalloxider som skola sammansattas hell eller delvis ersattas med foreningar, som vid upphettning kunna overga I dessa metallmdder, t. ex. karbonater, oxalater och acetater. Dessutom kan man ersatta de metalloxider som skola sammansattas belt eller delvis med minst en i forvag bildad reaktionsprodukt av tva eller flera av de metalloxider som skola sammansattas, t. ex. BaFe12019. Med »ratt forhallande» menas har ett forhallande av metallmangderna i utgangsblandningen, soil Sr ungefar lika med det i den fOrening som skall framstallas. The materials according to the invention can be prepared by heating (sintering) in oxygen or air of a selected, finely divided mixture of the metal oxides of the new compounds to be composed in a steering wheel, at a temperature above 1200 ° C. of the metal oxides which are to be composed in whole or in part are replaced by compounds which, on heating, can surpass in these metal forms, e.g. carbonates, oxalates and acetates. In addition, it is possible to replace the metal oxides which are to be composed in belt or in part with at least one precursor-formed reaction product of two or more of the metal oxides which are to be composed, e.g. BaFe12019. By "steering ratio" is meant a ratio of the amounts of metal in the starting mixture, soil Sr is approximately equal to that in the compound to be produced.

Eventuellt kan man forst forsintra det finfordelade utgangsmaterialet vid en forhallandevis lag temperatur (c:a 800°-1100° C) i luft eller Byre och pulvrisera reaktionsblandningen och pa nytt sintra det erhallna pulvret, varpâ dessa bearbetfinger kunna upprepas en eller flera ganger. Ett dylikt sintringsforfarande ar i och for sig kant t. ex. vid framstallning av ferromagnetiska jarnoxidforeningar (s. k. Aerriter») med spinellstruktur. Optionally, one can first pre-sinter the finely divided starting material at a relatively low temperature (about 800 ° -1100 ° C) in air or Byre and pulverize the reaction mixture and re-sinter the obtained powder, whereupon these processing fingers can be repeated one or more times. Such a sintering process is per se edge e.g. in the production of ferromagnetic iron oxide compounds (so-called aerrites) with spinel structure.

For underlattande av sintringen kan naturligtViS sintringsmedel sasom silikater eller fluorider tillsattas. A.v det har beskrivna ferromagnetiska materialet bestaende kroppar kunna antingen erhallas darigenom, att utgangsblandningen av metalloxiderna och liknande genast sintras i den Onskade formen eller darigenom, att reaktionsprodukten av fOrsintringen finmales och eventuellt efter tillsattning av ett bindemedel bringas i den onskade formen och eftersintras. To facilitate the sintering, natural sintering agents such as silicates or fluorides can be added. The existing bodies of the ferromagnetic material described can either be obtained by immediately sintering the starting mixture of the metal oxides and the like in the desired form or by finely grinding the reaction product of the pre-sintering and possibly after adding a binder to the desired shape and post-sintering.

HOgfrekvensegenskaperna hos material enligt uppfinningen kunna ofta ytterligare vasentligt fOrbattras, om vid framstallningen av dessa material man sorjer for, att dimensionerna hos de separata kristallerna icke bli for stora. Detta kan uppnas darigenom, att utgangsmaterialet fin-males noga och att man vid sintringen beaktar, att ingen stark kristalltillvaxt kan upptrada. Detta kan undvikas darigenom, att ett relativt 2- 184-487 - mattligt dvs. vanligtvis forhallandevis kort sintringsforlopp tillampas. Det maste betraktas som en overraskande omstandighet att hogfrekvensegenskaperna hos foreliggande material kunna fOrbattras pa det angivna sattet. Visserligen var det vid framstallningen av permanentmagnetiska material med formeln MO • 6Fe203 (varvid M betecknade barium, strontium eller bly) kant att anvdnda ett dylikt forfarande (se den franska patentskriften 1 048 792). Det galler darvid emellertid framstallningeri av permanentmagnetiska material, vid vilka man forsoker begransa magnetiseringsforloppen genom vaggforskjutningar for bibehallande av koerdtivfaitstyrkan hos namnda material pa ett Mgt varde. Materialen enligt uppfinningen aro emellertid icke permanentmagnetiska. The high-frequency properties of materials according to the invention can often be further substantially improved, if in the production of these materials care is taken that the dimensions of the separate crystals do not become too large. This can be achieved by grinding the starting material carefully and taking into account during sintering that no strong crystal growth can occur. This can be avoided by the fact that a relatively 2- 184-487 - matt ie. usually a relatively short sintering process is applied. It must be considered as a surprising circumstance that the high frequency properties of the present material can be improved in the manner indicated. Admittedly, in the production of permanent magnetic materials of the formula MO • 6Fe 2 O 3 (where M represented barium, strontium or lead) it was possible to use such a process (see French Pat. No. 1,048,792). This applies, however, to the production of permanent magnetic materials, in which an attempt is made to limit the magnetization processes by rock displacements in order to maintain the coercive strength of said material at a Mgt value. However, the materials of the invention are not permanently magnetic.

Det dr tydligt, att vid det beskrivna framstallningsforfarandet latt sma mangder av foreningar kunna upptrada i reaktionsprodukten. Exempel pa dylika fororeningar aro jamoxid och foreningar med spinellstruktur. It is clear that in the preparation process described, small amounts of compounds could be present in the reaction product. Examples of such impurities are jam oxide and compounds with spinel structure.

Vid framstallning av ferromagnetiska kroppar for anvdndning vid frekvenser pa 50 MHz och hogre kunna dessa material enligt uppfinningen naturligtvis anvandas i kombination med andra material med ungefar samma egenskaper betrOffande begynnelsepermeabiliteten och elektroinagnetiska forluster. In the manufacture of ferromagnetic bodies for use at frequencies of 50 MHz and above, these materials of the invention can, of course, be used in combination with other materials having approximately the same properties with respect to initial permeability and electro-magnetic losses.

Sasom redan anmarkts skilja sig foreningarna enligt uppfinningen genom begynnelsepermeabilitetsvardena, som Oro hogre och ofta avsevart hogre an 2, till och med vid frekvenser pa 50 MHz och ofta vid vasentligt hogre frekvenser. Yid kroppar som i stort sett besta av denna forening aro de elektromagnetiska forlusterna (uttryckta i forlustfaktorn tg(5), speciellt vid frekvenser Over 50 MHz 1 allmanhet mindre an vid kroppar, som besta av de kanda ferriterna med spinellstruktur. As already noted, the compounds of the invention differ by the initial permeability values, which are higher and often considerably higher than 2, even at frequencies of 50 MHz and often at substantially higher frequencies. Yid bodies which largely consist of this compound aro the electromagnetic losses (expressed in the loss factor tg (5), especially at frequencies Over 50 MHz 1 generally less than in bodies, which consist of the known ferrites with spinel structure.

For forklaring av det har anvanda uttrycket »tga» bor foljande observeras. I allmanhet medfor ett magnetiskt vaxelfalt med sma =pander i en ferromagnetisk kropp en induktans, som i det narmaste varierar sinusformigt. Pa grund av de elektromagnetiska forlusterna, uppstar en fasskillnad mellan faltstyrkan och induktansen. Det dr darfor vanligt att ange begynnelsepermeabiliteten for en ferromagnetisk kropp med en komplex storhet. Detta kan ske med uttrycket: itt = - Le. To explain this, the term "tga" has been used, the following should be observed. In general, a magnetic gear field with small pans in a ferromagnetic body causes an inductance which varies almost sinusoidally. Due to the electromagnetic losses, a phase difference arises between the field strength and the inductance. It is therefore common to indicate the initial permeability of a ferromagnetic body with a complex quantity. This can be done with the expression: itt = - Le.

Detta forhallande visar att induktansen kan betraktan som bestaende av tva komponenter, av vilka den ena är likfasig med det patryckta faltet och den andra fasforskjuten 90° efter detta fait. This ratio shows that the inductance can be regarded as consisting of two components, one of which is phased with the printed field and the other phase-shifted 90 ° after this fact.

Storhetenär den reella delen av begynnelse- permeabiliteten och anges i efterfoljande utforingsexempel. Forlustvinkeln 6 definieras enligt folj ande: tgo = Detta tgc5 betecknas hdr som forlustfaktor for det ferromagnetiska materialet. The quantity is the real part of the initial permeability and is given in the following embodiment. The loss angle 6 is defined as follows: tgo = This tgc5 is referred to hdr as the loss factor for the ferromagnetic material.

Exempel I. 39,8 g bariumkarbonat (69,1 viktprocent barium), 31,8 g koboltkarbonat (44,5 viktprocent kobolt), 19,3 g titanoxid (99,9 viktprocent TiO2) och 156,8 g jarnoxid (99,6 viktprocent Fe203) blandas. Dessa mangder dro sa valda att i ovannamnda formel a har vardet 1,2. Denna blandning males i en kulkvarn med alkohol under 15 timmar. Efter torkning fOrsintras blandningen under tva timmar vid 1100° C och males aterigenom pa samma att. Dart:a males pulvret i en skakkvarn fyra timmar annu en gang med alkohol. Av det efter torkningen erhallna pulvret pressas med ett tryck av 1,5 t/cm2 en ring som darph sintras i syre genom aft den far passera en ugn. Den 10 cm langa zonen i ugnen med maximal temperatur (1280° C) genomlopes under 6 minuter. Example I. 39.8 g of barium carbonate (69.1% by weight of barium), 31.8 g of cobalt carbonate (44.5% by weight of cobalt), 19.3 g of titanium oxide (99.9% by weight of TiO2) and 156.8 g of iron oxide (99% 6% by weight of Fe 2 O 3) is mixed. These quantities were so selected that in the above formula a the value has been 1.2. This mixture is ground in a ball mill with alcohol for 15 hours. After drying, the mixture is pre-sintered for two hours at 1100 ° C and ground again at the same time. Darts: grind the powder in a shaker for four hours once more with alcohol. From the powder obtained after drying, a ring is pressed with a pressure of 1.5 t / cm2, which must be sintered in oxygen by passing it through an oven. The 10 cm long zone in the oven with maximum temperature (1280 ° C) is run through for 6 minutes.

Exempel II (a = 1,35). 39,8 g bariumkarbonat, 35,8 g kobaltkarbonat, 21,6 g titanoxid och 151,9 g jarnoxid males, forsintras och males ater pa det i exempel I angivna sattet. Av det erhallna pulvret pressas en ring som sintras vid 1280° C (ring A), en ytterligare ring pressas och sintras vid 1350° C (ring B), hada i syre i en ugn enligt exempel I. Example II (a = 1.35). 39.8 g of barium carbonate, 35.8 g of cobalt carbonate, 21.6 g of titanium oxide and 151.9 g of iron oxide are ground, pre-sintered and ground again in the manner given in Example 1. From the obtained powder, a ring sintered at 1280 ° C (ring A) is pressed, a further ring is pressed and sintered at 1350 ° C (ring B), had in oxygen in an oven according to Example I.

Exempel III ( a-1,45). 39,8 g bariumkarbonat, 38,4 g koboltkarbonat, 23,2 g titanoxid och 148,6 g jarnoxid behandlas pa samma satt som i thregaende exempel. Slutsintringen sker vid 1350° C i syre. Example III (a-1.45). 39.8 g of barium carbonate, 38.4 g of cobalt carbonate, 23.2 g of titanium oxide and 148.6 g of iron oxide are treated in the same manner as in the following example. The final sintering takes place at 1350 ° C in oxygen.

Exempel IV (a = 1,6). 50,1 g bariumkarbonat, 52,0 g koboltkarbonat, 32,0 g titanoxid och 179,6 g jarnmdd males pa ovan beskrivet att. Efter torkning forsintras blandningen under tva timmar vid 1050° C och males darpa. Ater under 15 timmar i en kulkvam. Air det erhallna pulvret pressas under ett tryck av 1,5 ticm2 en ring, som under tva timmar sintras i syre i en stationar ugn yid 1320° C och langsamt avkylcs i ugnen. Example IV (a = 1.6). 50.1 g of barium carbonate, 52.0 g of cobalt carbonate, 32.0 g of titanium oxide and 179.6 g of iron are ground as described above. After drying, the mixture is pre-sintered for two hours at 1050 ° C and ground darpa. Eat for 15 hours in a ball chamber. The resulting powder is pressed under a pressure of 1.5 ticm2 a ring, which is sintered for two hours in oxygen in a stationary oven at 1320 ° C and slowly cooled in the oven.

Tab ell. Chart.

Magnetiska egenskaper. Magnetic properties.

Exempel a IJ lagfrekverts 83 MHz tg Ws 145 MHz 1iltg8 275 MHz 2tg8 500 MHz ILtg8 1,19 19 0,06 0,17 0, II ring A 1,19 17 0,08 17 0,12 18 0,4 II ring B 1,0,29 29 0,0,6 III 1,23 23 0,28 IV 1,6 6,2 - 5,2 0,18 — —3 Example a IJ layer frequency 83 MHz tg Ws 145 MHz 1iltg8 275 MHz 2tg8 500 MHz ILtg8 1.19 19 0.06 0.17 0, II ring A 1.19 17 0.08 17 0.12 18 0.4 II ring B 1.0.29 29 0.0.6 III 1.23 23 0.28 IV 1.6 6.2 - 5.2 0.18 - —3

Claims

Patent claim:

Ferromagnetic materials, in particular for ferromagnetic bodies for use at frequencies of at least 50 MHz, which consist essentially of mixed crystals with a structure similar to that of the compound BaFe1201 and of the formula BaCoa a (12-2a) 0 19 wherein 1.0

2. A ferromagnetic material according to claim 1, characterized in that in the given formula 1.2 <a <1.45.

A ferromagnetic body, which consists of a ferromagnetic material according to claim 1 or 2.

4. A process for producing a ferromagnetic material according to claim 1 or 2, or a ferromagnetic body according to claim 3, by heating a finely divided mixture of oxides of the metals to be composed, which may be replaced in whole or in part by compounds which upon heating over & in corresponding metal cods and / or with precursor-formed reaction products of two or more of the metal oxides which may be composed, characterized in that the finely divided mixture of the metal oxides which are to be composed and / or these substitute compounds is pre-sintered at a temperature radius of 800 ° C. and about 1100 ° C, whereby the chemical conversion takes place for the most part, the reaction product is finely ground and then optionally, with or without binder, given the shape desired for the ferromagnetic body and post-sintered at a temperature above 1200 ° C, preferably in an oxygen-rich gas atmosphere. . Request publications: