SE201503C1

SE201503C1 -

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Publication number: SE201503C1
Authority: SE
Publication date: 1965-01-01

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Uppfinnare: A Nerrot, Y CE Leseroel, B Grabowski och CL Guillaud Prioritet begard frdn den 1 juli 1955 (Frankrike) Foreliggande uppfinning avser ferromagnetiska material av ferrittypen, som ha vasentligen rektangular hysteresisslinga, samt fOrfaranden for framstallning av sadana material. Dylika material kunna anvandas i magnetiska uppteekningsanordningar kanda under benamningen »minnesanordningan, magnetiska styranordningar, magnetiska fOrstarkare och liknande. Vid dessa tillampningar anvandas material enligt uppfinningen vanligen i form av i huvudsak toroidformade karnor eller atminstone sasom slutna magnetiska kretsar utan luftgap. Inventors: A Nerrot, Y CE Leseroel, B Grabowski and CL Guillaud Priority requested from 1 July 1955 (France) The present invention relates to ferrite-type ferromagnetic materials having essentially rectangular hysteresis loops and processes for making such materials. Such materials can be used in magnetic detection devices known as the "memory device", magnetic control devices, magnetic amplifiers and the like. In these applications, materials according to the invention are usually used in the form of substantially toroidal cores or at least as closed magnetic circuits without air gaps.

Magnesiumferriter med rektangular hysteresisslinga, dvs. sadana som innehalla huvudsakligen tvavard magnesiumoxid och trevard jarnoxid aro tidigare kanda. Foreliggande uppfinning avser ferriter med rektangular hysteresslinga, vilka joke innehalla magnesiumcodd. Magnesium ferrites with rectangular hysteresis loop, ie. those which contain mainly double magnesium oxide and trivalent iron oxide are formerly known. The present invention relates to ferrites with a rectangular hysteresis loop, which jokes contain magnesium cod.

Uppfmningen avser ferromagnetiska keramiska material med vasentligen rektangular hysteresisslinga och bestaende av reaktionsprodukten av en blandning av oxider av trevarda metaller, av vilka en är ferrioxid, samt oxider av tvavarda metaller, kannetecknat av att narnnda blandning innehaller mellan 30 och 52 molprocent i form av ferrioxid eller ferrioxid tillsammans med aluminiumoxid och/eller kromoxid, varvid proportionen aluminiumoxid och/eller kromoxid, om dessa finnas narvarande, icke overstiger en fjardedel av proportionen ferrioxid, manganoxid samt atminstone en av oxiderna nickeloxid och kopparoxid, varvid summan av molproportionerna manganoxid, nickeloxid och kopparoxid ligger mellan 33 och 70 procent, dar nickeloxiden är maximalt 20 molprocent och kopparmdden maximalt 15 molprocent av totala oxidinnehallet, samt summan av nicekloxid och kopparoxid ligger mellan 2 molprocent och Mitten av molprocentinnehallet manganoxid, och 0-15 molprocent av atminstone en av oxiderna zinkoxid och kadmiumoxid, varvid summan av molproportionerna ferrioxid eller ferrioxid med aluminiumcodd och/eller kromoxid, manganoxid, nickeloxid och/eller kopparoxid och, om det finns narvarande, zinkoxid och/eller kadmiumoxid utgor 100 % utan namnvarda mangder av andra metallmdder. The invention relates to ferromagnetic ceramic materials having a substantially rectangular hysteresis loop and consisting of the reaction product of a mixture of oxides of solid metals, one of which is ferric oxide, and oxides of divalent metals, characterized in that said mixture contains between 30 and 52 mol% in the form of ferric oxide or ferric oxide together with alumina and / or chromium oxide, the proportion of alumina and / or chromium oxide, if present, not exceeding one quarter of the proportion of ferric oxide, manganese oxide and at least one of the oxides nickel oxide and copper oxide, the sum of the molar proportions being manganese oxide, nickel oxide and copper oxide between 33 and 70 percent, where the nickel oxide is a maximum of 20 mole percent and the copper content a maximum of 15 mole percent of the total oxide content, and the sum of nicloxide and copper oxide is between 2 mole percent and the middle mole percent content of manganese oxide, and 0-15 mole percent of at least one of the oxides zinc oxide. and cadmium oxide, the sum of the molar proportions of ferric oxide or ferric oxide with aluminum cod and / or chromium oxide, manganese oxide, nickel oxide and / or copper oxide and, if present, zinc oxide and / or cadmium oxide being 100% without significant amounts of other metal.

I det fall att coddblandningen innehaller kopparoxid men ingen nickeloxid, ar summan av molprocenttalet av trevarda metalloxider mellan 40 och 52, summan av molprocenten mangan och kopparwdder mellan 35 och 55 samt molprocenten kopparoxid Indian 2 och 15. In case the codend mixture contains copper oxide but no nickel oxide, the sum of the mole percentages of trivalent metal oxides is between 40 and 52, the sum of the mole percentages of manganese and copper values between 35 and 55 and the mole percent of copper oxide Indian 2 and 15.

I det fall att oxidblandningen innehaller nickeloxid men ingen kopparoxid, är molprocenten nickeloxid mellan 2 och 20. In case the oxide mixture contains nickel oxide but no copper oxide, the mole percent nickel oxide is between 2 and 20.

Om mddblandningen innehaller bade nickeloxid och kopparoxid, är molprocenten kopparoxid mellan 2 och 20. If the medium mixture contains both nickel oxide and copper oxide, the mole percent copper oxide is between 2 and 20.

Materialen enligt uppfinningen uppvisar rektangulara hysteresisslingor, vilka ha en rektangularitetskoefficient artminstone lika med 0,90 och specifika motstand 'Must lika med 10 ohmeentimeter. Dessutom ha materialen hoga magnetiska flodestatheter vid 20° C, koercitivkraften mellan 0,2 och 3 Orstedt, Curiepunkter hogre an 150° C och en koefficient fOr variationerna av flodestatheten med temperaturen hOgst lika med 0,5. The materials according to the invention have rectangular hysteresis loops which have a rectangularity coefficient of at least equal to 0.90 and specific resistances' Must equal to 10 ohme centimeters. In addition, the materials have high magnetic river states at 20 ° C, the coercive force between 0.2 and 3 Orstedt, Curie points higher than 150 ° C and a coefficient for the variations of the river state with the temperature at most equal to 0.5.

Fastan materialen aro reaktionsprodukter av en blandning av oxider innehallande manganoxid, kan en annan manganoxid t. ex. Mn304 ursprungligen blandas med de andra oxiderna, eftersom varmebehandlingen leder till bildningen av manganomdd MnO och sedan reaktion mellan MnO och de andra oxiderna. Denna reaktion kan inbe- 2 gripa uppkomst av Mn20, och dennas reaktion med de andra oxiderna sasom nedan forklaras. Although the materials are reaction products of a mixture of oxides containing manganese oxide, another manganese oxide may e.g. Mn304 is initially mixed with the other oxides, as the heat treatment leads to the formation of manganese-containing MnO and then reaction between MnO and the other oxides. This reaction may involve the formation of Mn 2 O, and its reaction with the other oxides as explained below.

Materialens enligt uppfinningen egenskap att ha rektangularitet has hysteresisslingan beror pa narvaron av en avsevard mangd ferrit, som har star magnetostriktoinskoefficient. The property of the materials according to the invention to have rectangularity has the hysteresis loop due to the presence of a considerable amount of ferrite, which has a strong magnetostrictoine coefficient.

Det är kant att magnetostriktionen has en blandad ferrit beror pa magnetostriktionen has var och en av de ferriter, av vilka den är sammansatt. Bland alla ferriter ar det endast en namligen ferriten av jam eller magnetisk jarnoxid FeO. Fe203 (dvs. Fe304), som uppvisar en positiv magnetostriktionskoefficient. It is true that the magnetostriction has a mixed ferrite because the magnetostriction has each of the ferrites of which it is composed. Among all ferrites, there is only one, namely the ferrite of jam or magnetic iron oxide FeO. Fe203 (ie Fe304), which has a positive magnetostriction coefficient.

Enligt uppfinningen erhalles ett material medvasentligen rektangular hysteresisslinga genom bildning av en ferrit, som har foga eller inget tvavart jam. I dessa ferriter, van i molprocenten Fe203 är mindre an eller lika med 52, synes en del av mangnanoxiden bliva omvandlad till MnO, sa att det foreligger i huvudsak likhet mellan antalet molekyler innehallande metaller i trevart tillstand och antalet molekyler innehallande me-taller i tvavart tills-Land. According to the invention, a material with a substantially rectangular hysteresis loop is obtained by forming a ferrite which has a joint or no double yarn. In these ferrites, used in the mole percent Fe 2 O 3 is less than or equal to 52, some of the manganese oxide appears to be converted to MnO, so that there is essentially similarity between the number of molecules containing metals in the triple state and the number of molecules containing metals in two until-Land.

I den foljande beskrivningen aro de angivna -sammansattningarna utgangssaminansattningarna, innan oxiderna redu.cerats till lint pulver genom malning, Okningen i jarninnehallet pa grund .av notningen i kvarnen -dr vid en genomsnittlig kvarn ma 0-8 molekyler Fe203 per hundra mole-kyler malet material; varvid de angivna procenttalen Fe203 efter malningen maste okas med denna mangd. Korrektioner maste gOras, am en kvarn anvandes, som notes langsammare eller snabbare. In the following description, the stated compositions are the starting aggregates, before the oxides are reduced to lint powder by grinding. The increase in iron content due to the grinding in the mill is at an average mill of 0-8 molecules of Fe 2 O 3 per hundred molecules of the mill. material; whereby the stated percentages of Fe 2 O 3 after grinding must be increased by this amount. Corrections must be made when a grinder is used, which notes slower or faster.

Uppfinningen kommer atti detalj beskrivas i -det foljande i anslutning till utforingsexempel och I samband med bifogade ritningar. The invention will be described in detail in the following in connection with exemplary embodiments and in connection with the accompanying drawings.

Fig. 1 visar en i huvudsak rektangular hysteresisslinga. Fig. 1 shows a substantially rectangular hysteresis loop.

Fig. 2 visar ett triangeldiagram angivande ut-gangssammansattningarna av materialen enligt uppfinningen i det allmanna fallet. Fig. 2 shows a triangular diagram indicating the starting compositions of the materials according to the invention in the general case.

Fig. 3 visar etttriangeldiagram angivande utgangssammansat-tningarna for materialen enligt uppfinningen i det fallet, d ingen nickeloxid forefinnes. Fig. 3 shows a triangular diagram indicating the starting compositions of the materials according to the invention in the case where no nickel oxide is present.

Fig. 4 visar variationerna av B., Hem och fl sasom funktion av molprocenten nickeloxid. Fig. 4 shows the variations of B., Hem and fl as a function of the mole percent nickel oxide.

Fig. 5 visar variationerna av B., Hem och fim sasom funktion av molprocenten kopparcodd. Fig. 6 visar h3rsteresisslingorna for material av olika slag sammansattningar. Fig. 5 shows the variations of B., Hem and fim as a function of the mole percent copper cod. Fig. 6 shows the hairline loops for materials of different types of compositions.

Fig. 7 visar variationema av B., He. och /3m som funktion av molprocenten zinkcodd. Fig. 7 shows the variations of B., He. and / 3m as a function of the molar percentage of zinc cod.

Fig. 8, 9 och 10 representera variationerna has /3., R. och Km som funktion av fdltstyrkan H. vid nagra exempel pa material enligt uppfinningen. Figs. 8, 9 and 10 represent the variations has / 3., R. and Km as a function of the field strength H. in some examples of materials according to the invention.

Fig. 11 visar variationema av flodestatheten B. som funktion av arbetstemperaturen vid ett exempel pa material enligt uppfinningen. Fig. 11 shows the variations of the river state B. as a function of the operating temperature in an example of material according to the invention.

Fig. 12 visar hysteresisslingorna vid olika be handlingstemperaturer for ett material enligt uppfinningen. Fig. 12 shows the hysteresis loops at different treatment temperatures for a material according to the invention.

Fig. 13 visar variationen av flOdestatheten Bm som funktion av behandlingstemperaturen vid olika sammansattningar i enlighet med uppfinningen. Fig. 13 shows the variation of the flow state Bm as a function of the treatment temperature at different compositions in accordance with the invention.

Fig. 14 visar variationerna av an som funktion av molprocenten kopparoxid. Fig. 14 shows the variations of an as a function of the mole percent copper oxide.

Fig. 15-19 och 21-23 visa hysteresisslingorna Mr material enligt uppfinningen.-- Fig. 20 visar variationerna av B., Hem och flm som funktion av behandlingstemperaturen for ett material enligt uppfinningen. Figs. 15-19 and 21-23 show the hysteresis loops Mr material according to the invention. Fig. 20 shows the variations of B., Hem and flm as a function of the treatment temperature for a material according to the invention.

I fig. 1, som avser en rektangular hysteresisslinga motsvarande faltstyrkan H, visas nodestatheten Em = OR, remanensen B ern = OP, filodestatheten Bdm = OS och motsvarande ett magnetiseringsfalt (—H./2), liksom awn koercitivkraften Hem. In Fig. 1, which refers to a rectangular hysteresis loop corresponding to the field strength H, the node state Em = OR, the remnant B ern = OP, the phylode state Bdm = OS and corresponding to a magnetization field (—H./2) are shown, as well as the coercive force Hem.

FOr rektangularitetskoefficienten galler Br. OP 13fli — B. ----- —OR .Koefficienten for variationen av 13. som funktion av temperaturen betecknas genom 1 4B. an = 2 B At dar AB. dr flodestathetsandringen mellan 20 och 60° C och At am motsvarande temperaturandring, dvs. 40° C. For the rectangularity coefficient, Br. OP 13fli - B. ----- —OR .The coefficient of variation of 13. as a function of temperature is denoted by 1 4B. an = 2 B At dar AB. dr river state change between 20 and 60 ° C and At am corresponding temperature change, ie. 40 ° C.

Bchn OS rtni - = Bin OW och for forhallandet K.: OP + OT Brm Brn OP — OS Brm —Bdm Det skall observeras att om 18. = 1—a erhalles 3 R. -< 1 Fig. 2 visar ett triangeldiagram motsvarande ett material enligt uppfinningen, varvid de tre komponenterna aro: Fe202-molekylerna, Zn0- -molekylerna och summan av antalet MnO-NiOoch CuO-molekylerna, varvid det totala antalet molekyler dr lika med 100. Den figurativa punk-ten for sammansattningen med en rektangular hysteresisslinga kommer att befinna sig inom den -skuggade zonen, 1, 2, 3, 4 och 5. Bchn OS rtni - = Bin OW and for the ratio K .: OP + OT Brm Brn OP - OS Brm —Bdm It should be noted that if 18. = 1 — a is obtained 3 R. - <1 Fig. 2 shows a triangle diagram corresponding to a materials according to the invention, wherein the three components are: the Fe 2 O 2 molecules, the ZnO - molecules and the sum of the number of MnO-NiO and CuO molecules, the total number of molecules being equal to 100. The figurative point of the composition with a rectangular hysteresis loop will be within the shaded zone, 1, 2, 3, 4 and 5.

Granserna motsvara foljande sammansattningar Punkt 1: 52 FeO 3, [48—(v + w)] MnO, vNiO, wCuO. 3 Punkt 2:52 Fe203, [33-(v + w)] MnO, cNiO, 15 ZnO, wCuO. The boundaries correspond to the following compositions Point 1: 52 FeO 3, [48— (v + w)] MnO, vNiO, wCuO. 3 Point 2:52 Fe 2 O 3, [33- (v + w)] MnO, cNiO, 15 ZnO, wCuO.

Punkt 3: 40 Fe203, [45-(v + w)] • MnO, cNiO, wCuO, 15 ZnO, Punkt 4: 30 Fe203, [60-(v + w)] MnO, vNiO, wCuO, 10 ZnO. Point 3: 40 Fe 2 O 3, [45- (v + w)] • MnO, cNiO, wCuO, 15 ZnO, Point 4: 30 Fe 2 O 3, [60- (v + w)] MnO, vNiO, wCuO, 10 ZnO.

Punkt 5: 30 Fe03, [70-(v + w)] • MnO, vNiO, wCuO. Item 5: 30 FeO 3, [70- (v + w)] • MnO, vNiO, wCuO.

Skalen for dessa granser, som am angivna Rh' zonerna, Oro: till hoger am 1,2 blir magnetostriktionskoefficienten A3 positiv och darfor forsvinner rektangulariteten hos hysteressislingan. OvanfOr 3,2 blir pa grund av det hoga zinkinnehallet ferriten mjukare och dess Curiepunkt sjunker. Rektangulariteten has hysteresisslingan Or icke sA. god vid rumstemperatur. Till vanster am eller under 3,4 blir Curiepunkten Oven alltfor lag. The scales for these boundaries, such as the indicated Rh 'zones, Oro: to the right am 1,2, the magnetostriction coefficient A3 becomes positive and therefore the rectangularity of the hysteresis loop disappears. Above 3.2, due to the high zinc content, the ferrite becomes softer and its Curie point decreases. The rectangularity has the hysteresis loop Or icke sA. good at room temperature. To the left am or below 3.4, the Curie point above becomes too low.

Det foljer harav att aB kan bli hogre On 0,5 ovanfor linjen 3,4, medan rektangulariteten fortfarande blir acceptabel. Slutligen sjunker till vanster am eller utanfor 4,5 momentet vid mattning till ett varde, som är alltfor lagt for att kunna Fig. 3 visar ett triangeldiagram for ett ferromagnetiskt material, som liar utgangssammansattningen X Fe2O3, uMnO, wCuO, sZnO. dvs. utgangssammansattningen i enlighet med uppfinningen i det fallet, da den icke innehaller nagon nickelmdd. It follows that aB may be higher On 0.5 above line 3.4, while the rectangularity will still be acceptable. Finally, it drops to the left am or outside the 4.5 moment when mating to a value which is too low to be able to Fig. 3 shows a triangular diagram of a ferromagnetic material, which has the initial composition X Fe2O3, uMnO, wCuO, sZnO. i.e. the starting composition according to the invention in the case where it does not contain any nickel content.

Om 2 < w < 5, Or den zon, som skall betraktas, den skuggade zonen 6, 7, 10, 11, 12. If 2 <w <5, Or the zone to be considered, the shaded zone 6, 7, 10, 11, 12.

Om 5 < w < 15, Or den zon, som skall betraktas, hela den skuggade zonen 6, 8, 9, 10, 11, 12. If 5 <w <15, Or the zone to be considered, the whole shaded zone 6, 8, 9, 10, 11, 12.

Tillsatsen av kopparoxid till ferriten gOr det mojligt aft i sjalva verket Oka Curiepunkten has materialet, varvid kopparferriten har en Curiepunkt av storleksordningen 450° C. Det Mier harav att zinkoxid kan tillforas i storm mangd under bibehallande av de hada ovan namnda egenskaperna: Pm <0,90 och aB < 0, De sammansattningar, som begransa diagram-met 6, 8, 9, 10, 11, 12, Oro: Punkt 6: 52 Fe303, (48-w) MnO, wCuO Punkt 8: 50 Fe203, (35-w) MnO, wCuO, 15 ZnO. Punkt 9: 45 Fe203, (40-w) MnO, wCuO, 15 ZnO. Punkt 10: 40 Fe303, (50-w) MnO, wCuO, 10 ZnO. Punkt 11: 40 Fe203, (55-w) MnO, wCuO, 5 ZnO. Punkt 12: 50 Fe203, (50-w) MnO, wCuO. The addition of copper oxide to the ferrite makes it possible to in fact increase the curie point of the material, the copper ferrite having a curie point of the order of 450 ° C. It is believed that zinc oxide can be added in large quantities while maintaining the above mentioned properties: Pm <0 , 90 and aB <0, The compositions which delimit the diagrams 6, 8, 9, 10, 11, 12, Concerns: Point 6: 52 Fe303, (48-w) MnO, wCuO Point 8: 50 Fe203, ( 35-w) MnO, wCuO, 15 ZnO. Item 9: 45 Fe 2 O 3, (40-w) MnO, wCuO, 15 ZnO. Item 10: 40 Fe 3 O 3, (50-w) MnO, wCuO, 10 ZnO. Item 11: 40 Fe 2 O 3, (55-w) MnO, wCuO, 5 ZnO. Item 12: 50 Fe 2 O 3, (50-w) MnO, wCuO.

Formen has diagrammen kan fOrklaras pa f 01- jande sat: Tillsatsen av ZnO ger det mojligt att Oka momentet vid mattning has materialet, sa att med ett innehall av ZnO-molekyler mellan 5 och 10 det Or mojligt att ga ned till ett innehall av Fe203- molekyler av storleksordningen 40. The shape of the diagrams can be explained in the following way: The addition of ZnO makes it possible to increase the moment during matting of the material, so that with a content of ZnO molecules between 5 and 10 it is possible to decrease to a content of Fe molecules of the order of 40.

For innehall av ZnO-molekyler storm On 10 blir zonen trangre. Minimiinnehallet av Fe20 rmolekyler maste yam hogre och hogre for att an skall Ni minst lika med 0,5. For content of ZnO molecules storm On 10, the zone becomes narrower. The minimum content of Fe20 molecules must be higher and higher so that you must be at least equal to 0.5.

I vart och ett av triangeldiagrammen, fig. 2 eller fig. 3, kan en del eller alit ZnO ersattas av kadmiumoxid CdO med liten eller foga inverkan pa de jamforda egenskaperna has materialen. In each of the triangle diagrams, Fig. 2 or Fig. 3, some or all of the ZnO may be replaced by cadmium oxide CdO with little or no effect on the comparative properties of the materials.

I fig. 4 visas variationerna av B., He. och jens has blandningar med 50 Fe30, (50-v) MnO, vNiO, sasom funktion av innehallet v av N10- molekyler. De material, som ha betraktats, ha glodgats vid 1240° C under fyra timmar i ren kvavgas innehallande en volymsprocent syre. Kylningen sker i rent kvave. De magnetiska egenskaperna erhallas Iran statiska slingor upptagna f Or ett falt H. = 2 orstedt. Variationen has fins Or mycket liten, under det att B. minskar och Hem iikar, d5 v Okar. Fig. 4 shows the variations of B., He. and jens has mixtures with 50 Fe 3 O, (50-v) MnO, vNiO, as a function of the content v of N10 molecules. The materials which have been considered have been annealed at 1240 ° C for four hours in pure nitrogen containing one% by volume of oxygen. The cooling takes place in pure suffocation. The magnetic properties are obtained Iran static loops occupied f Or a field H. = 2 orstedt. The variation has been Or very small, while B. decreases and Hem iikar, d5 v Okar.

Fig. 5 representerar vid fallet en mangan- och kopparferrit variationerna av karakteristikorna /3. och Hem som funktion av molprocenten w av CuO for ett maximifalt Hm = 2 orstedt. De ferriter, som jamfaras, ha den allmanna formeln 50 Fe203, (50-w) MnO, wCuO. Fig. 5 in the case of a manganese and copper ferrite represents the variations of the characteristics / 3. and Hem as a function of the mole percentage w of CuO for a maximum Hm = 2 orstedt. The ferrites compared have the general formula 50 Fe 2 O 3, (50-w) MnO, wCuO.

Det skall observeras att B. minskar, under det att Hem okar, da CuO-innehallet 'Aar, under det att pm praktiskt taget icke varierar och forblir nara lika med 0,95. It should be noted that B. decreases, while Hem increases, as the CuO content 'Aar, while pm practically does not vary and remains almost equal to 0.95.

Fig. 6 visar hysteresisslingorna motsvarande ett fait Hm = 2 orstedt for fyra material, som ha foljande sammansattningar i molprocent: 50 Fe203, 50 MnO, 50 Fe203, 45 MnO, 5 CuO, 50 Fe203, 40 MnO, 10 CuO, 50 Fe203, 30 MnO, 10 CuO, 10 ZnO. Fig. 6 shows the hysteresis loops corresponding to a fait Hm = 2 orstedt for four materials, which have the following compositions in mole percent: 50 Fe 2 O 3, 50 MnO, 50 Fe 2 O 3, 45 MnO, 5 CuO, 50 Fe 2 O 3, 40 MnO, 10 CuO, 50 Fe 2 O 3, 30 MnO, 10 CuO, 10 ZnO.

Kurvorna i fig. 4, 5 och 6 visa att tillsatsen av CuO- eller NiO-molekyler gor det mojligt att pa ett visst sat reglera flodestatheten och koercitivkraften Mom cyklen for ett material, som har ett bestamt innehall av Fe03-molekyler. The curves in Figures 4, 5 and 6 show that the addition of CuO or NiO molecules makes it possible to regulate in a certain way the river state and the coercive force Mom cycle for a material which has a certain content of FeO3 molecules.

Fig. 7 visar vid fallet en mangan-koppar- och zinkferrit variationerna av karakteristikorna B., pm och Hem sasom funktion av molprocenten ZnO for ferriter, vilkas utgangssammansattning i molprocent Oro: 50 Fe203, (40-s) MnO, 10 CuO, sZnO. Fig. 7 shows in the case of a manganese-copper and zinc ferrite the variations of the characteristics B., pm and Hem as a function of the molar percentage ZnO for ferrites, the starting composition of which in mol% Oro: 50 Fe 2 O 3, (40-s) MnO, 10 CuO, sZnO .

Det skall observeras att B. nagot okar, under det att Hem snabbt minskar, da innehallet Zn0- molekyler okas, under det att 13m praktiskt taget icke varierar och fiirblir mellan 0,95 och 0,94. It should be noted that B. slightly increases, while Hem decreases rapidly, as the content of ZnO molecules increases, while 13m practically does not vary and remains between 0.95 and 0.94.

I fig. 8, 9 och 10 representeras variationerna av karakteristikorna fins, R. och K. sasom funktion av magnetiseringsfaltet. Fig. 8 haul Or sig till material, vilkas molekylara sammansattning an 50 Fe203, 35 MnO, 15 NiO, R. ochuppna sina 4 maximivarden i narheten av ett falt Hm = 1,4 orsted. Fig. 9 hfinf or sig till ett material, vars molsammansattning är 46,7 Fe202, 32,8 MnO, 7,0 ZnO, 13,5 NiO. R. och K uppna sina maximivarden i narheten av faltstyrkan Hn„ = 2,50 orsted. De variera mycket saktare i narheten av maximivardet an vid det i fig. 8 visade exemplet. In Figs. 8, 9 and 10, the variations of the characteristics fins, R. and K. are represented as a function of the excitation field. Fig. 8 haul Or to materials whose molecular composition of 50 Fe 2 O 3, 35 MnO, 15 NiO, R. and open their 4 maximum values in the vicinity of a field Hm = 1.4 orsted. Fig. 9 refers to a material whose molar composition is 46.7 Fe 2 O 2, 32.8 MnO, 7.0 ZnO, 13.5 NiO. R. and K reach their maximum values in the vicinity of the field strength Hn „= 2.50 orsted. They vary much more slowly in the vicinity of the maximum value than in the example shown in Fig. 8.

Fig. 10 representerar variationerna 9m, R och K. sasom funktion av magnetiseringsfalten H. fiir den ferrit, som har foljande sammansattning i molprocent: 50 Fe203, 30 MnO, 10 CuO, 10 ZnO. Fig. 10 represents the variations 9m, R and K. as a function of the excitation field H. for the ferrite, which has the following composition in mole percent: 50 Fe 2 O 3, 30 MnO, 10 CuO, 10 ZnO.

Fdltstyrkan H. är optimal for ett varde nara 0,8 orsted, for vilket 16. = 0,94, R. — 0,77 oak = 11,7. The field strength H. is optimal for a value close to 0.8 orsted, for which 16. = 0.94, R. - 0.77 oak = 11.7.

Materialen motsvarande fig. 8, 9 och 10 ha behandlats under samma villkor som materialen motsvarande fig. 4. The materials corresponding to Figs. 8, 9 and 10 have been treated under the same conditions as the materials corresponding to Figs. 4.

Fig. 11 visar variationerna av flodestdtheten B. for en slinga uppritad Mr en faltstyrka H. = 2 orsted, sdsom funktion av behandlingstemperaturen. Kurvan hanfOr sig till ett material, vars sammansattning i molprocent är fOljande: 50 Fe203, 35 MnO, 15 NiO, varvid materialet behandlats pa samma satt och som materialen i fig. 4. Fig. 11 shows the variations of the river density B. for a loop plotted Mr a field strength H. = 2 orsted, as a function of the treatment temperature. The curve refers to a material whose composition in mole percent is as follows: 50 Fe 2 O 3, 35 MnO, 15 NiO, the material being treated in the same way as the materials in Fig. 4.

Vardet av an kan beraknas och är lika med 0,2. The value of an can be calculated and is equal to 0.2.

Fig. 12 representerar olika slingor for ett falt H. = 2 orsted vid olika temperaturer for det material, som redan hehandlats i exemplet i fig. 11. Slingorna aro angivna for temperaturerna 20° C, 40° C och 70° C. Fig. 12 represents different loops for a field H. = 2 orsted at different temperatures for the material already treated in the example in Fig. 11. The loops are indicated for the temperatures 20 ° C, 40 ° C and 70 ° C.

Fig. 13 och 14 visa inflytandet av CuO-molekylerna pa variationerna hos de magnetiska egenskaperna sasom funktion av temperaturen. Figures 13 and 14 show the influence of the CuO molecules on the variations of the magnetic properties as a function of temperature.

Fig. 13 visar en variation av B. som funktion av temperaturen for en faltsLyrka Hm = 2 Orsted, for material, vilkas sammansattning i molprocent ar: 50 Fe203, 50 MnO, 50 Fe20„ 45 MnO, 5 CuO, 50 Fe203, 40 MnO, 10 CuO, 50 Fe203, 30 MnO, 10 CuO, 10 ZnO. Fig. 13 shows a variation of B. as a function of the temperature for a fieldLyrka Hm = 2 Orsted, for materials, the composition of which in mole percentages is: 50 Fe 2 O 3, 50 MnO, 50 Fe 2 O 4 45 MnO, 5 CuO, 50 Fe 2 O 3, 40 MnO , 10 CuO, 50 Fe 2 O 3, 30 MnO, 10 CuO, 10 ZnO.

Det skall darfor observeras att tillsatsen av CuO-molekyler gor det mojligt att reducera variationerna hos B. som funktion av temperaturen mellan 0 och 100° C, men att narvaron av Zn0- molekyler har motsatt verkan. It should therefore be noted that the addition of CuO molecules makes it possible to reduce the variations of B. as a function of the temperature between 0 and 100 ° C, but that the presence of ZnO molecules has the opposite effect.

Fig. 14 visar variationerna av an som funktion av innehallet CuO-molekyler i ferriter, varvid raga' ngssammansattningen i molprocent är: 50 Fe2O3 (50—v) MnO, vCuO. varvid det skall observeras av for v = 5 och s =-- 0 erhalles an = 0,1. Fig. 14 shows the variations of an as a function of the content of CuO molecules in ferrites, the rag composition in mole percent being: 50 Fe 2 O 3 (50-v) MnO, vCuO. whereby it must be observed that for v = 5 and s = - 0 is obtained an = 0.1.

Tillverlaringsmetod. De anyanda oxidernas sammansattning och natur. blandningarna anvandes ferrioxid Fe203, salin manganoxid Mn304 eller t. o. m. manganoxider Mn0 2 eller Mn203 eller 11,1n0 eller en blandning av dessa oxider, niekelmdd NiO, kopparoxid CuO och zinkoxid ZnO. Dessa oxider maste yam rena och blandningarna f icke innehallet mer an 0,5 % fororeningar. Kise1oxid (Si02), bariumcodd (BaO), blyoxid Pb0), strontiumoxid (Sr0), etc. Oro speciellt skadliga, eftersom ndrvaron av dessa fororeningar tenderar att avrunda hysteresisslingans horn. Production method. The composition and nature of anya oxide. the mixtures used ferric oxide Fe 2 O 3, saline manganese oxide Mn 3 O 4 or even manganese oxides MnO 2 or Mn 2 O 3 or 11.1nO or a mixture of these oxides, niekelmdd NiO, copper oxide CuO and zinc oxide ZnO. These oxides must be pure and the mixtures must not contain more than 0.5% impurities. Silica (SiO2), barium cod (BaO), lead oxide (Pb0), strontium oxide (Sr0), etc. Concerns are particularly harmful, as the presence of these impurities tends to round the horns of the hysteresis loop.

Innehallet av var och en av dessa fororeningar maste vara mindre an 0,05 viktprocent. The content of each of these impurities must be less than 0,05% by weight.

Malning. Oxidblandningen males i en jarnkvarn med stalkulor vanligen under 12-48 timmar med en viktsmangd destillerat vatten av c:a dubbla oxidblandningens vikt. Painting. The oxide mixture is ground in an iron mill with steel balls, usually for 12-48 hours with a weight amount of distilled water of about twice the weight of the oxide mixture.

Pressning. Inflytandet av det tryck, som uttivas vid pressningen, ãr avsevart. Det maste vara tillrackligt stort for att mattningsmomentet has slutprodukten skall bli tillrackligt hog och a andra sidan tillrackligt lagt for att krympningen under sintringen skall bli avsevard. Pressing. The influence of the pressure exerted during the pressing is considerable. It must be large enough for the matting moment to have the end product to be sufficiently high and, on the other hand, sufficiently laid for the shrinkage during sintering to be considerable.

Ett tryck av c:a 5 ton per kvadratcentimeter, vilket motsvarar en linjar krympning pa c:a 15 %, har givit goda resultat. Det Or miijligt att gá fran 0,5 till 15,0 ton per kvadratcentirneter. A pressure of about 5 tons per square centimeter, which corresponds to a linear shrinkage of about 15%, has given good results. It is possible to go from 0.5 to 15.0 tons per square centimeter.

Varmebehandlingarna. Den pa angivet satt erhallna produkten underkastas en varmebehandling hesthende i upphettning vid en temperatur mellan 900° C och 1350° C i rent kvave med en tillsats av 1-20 volympro cent syre, eller i vissa fall i luft, atfoljd av langsam avkylning afford under c:a 15 timmar. The heat treatments. The product obtained in this way is subjected to a heat treatment horse in heating at a temperature between 900 ° C and 1350 ° C in pure nitrogen with the addition of 1-20% by volume of oxygen, or in some cases in air, followed by slow cooling afforded during about 15 hours.

FOr att erhalla optimala egenskaper maste temperaturen och glodgningsatmosfaren installas experimentellt fOr varje sammansattning. In order to obtain optimal properties, the temperature and annealing atmosphere must be installed experimentally for each composition.

Urn utgangsblandningen icke innehiller nagon nickeloxid maste glocIgningstemperaturen ligga mellan 1000° C och 1300° C. Ju mer kopparcodd, som ingar i ferriten, desto mer maste glocigningstemp eraturen minskas. For nollinnehall av kopparoxid CuO, erhfillas mycket goda resultat vid c:a 1250° C, for 10 °/, CuO, är det nodvandigt att gloclga vid c:a 1200° C och for 15 % CuO gem en temperatur av 1150° C tillfredsstallande resultat. Om utgangsblandningen innehaller nickeloxid maste glodgningstemperaturen ligga mellan 1000° C och 1350° C. Betraffande glocIgningsatmosfaren maste, ju mer nickel- och kopparoxider som innehallas i ferriten, glodgningsaLmosfaren vara rik pa syre och i atskilliga fall Or glodgning mojlig i luft, vilket är mycket lampligt och utgor ett kannetecken for uppfinningen. If the starting mixture does not contain any nickel oxide, the glazing temperature must be between 1000 ° C and 1300 ° C. The more copper cod which enters the ferrite, the more the glazing temperature must be reduced. For zero content of copper oxide CuO, very good results are obtained at about 1250 ° C, for 10 ° /, CuO, it is necessary to gloglga at about 1200 ° C and for 15% CuO save a temperature of 1150 ° C satisfactory results. If the starting mixture contains nickel oxide, the annealing temperature must be between 1000 ° C and 1350 ° C. Regarding the annealing atmosphere, the more nickel and copper oxides contained in the ferrite, the annealing atmosphere must be rich in oxygen and in several cases annealing is possible in air, and is a hallmark of the invention.

Vid en annan utfOrings-form av uppfinningen kan det malda pulvret fore pressningen underga en fiir-sintring vid en temperatur mellan 600° C och 1200° C, lampligen vid c:a 1000° C. Temperaturen vid denna for-sintring maste sa installas, att den slutliga krympningen hos materialet atminstone blir htigre an 8 %. In another embodiment of the invention, the ground powder for pre-pressing may undergo a pre-sintering at a temperature between 600 ° C and 1200 ° C, suitably at about 1000 ° C. The temperature of this pre-sintering must then be installed. that the final shrinkage of the material is at least 8% higher.

Det skall observeras att vid en blandning, som behandlad pa normalt satt uppvisar goda rektangularitetsegenskaper, en for-sintring vid alltfOr hog temperatur (exempelvis 1200° C) leder till krympning av storleksordningen 4 %, vilket ger material, som joke ha nagon rektangular hysteresisslinga. It should be noted that in a mixture which is normally treated with good rectangularity properties, a pre-sintering at too high a temperature (for example 1200 ° C) leads to shrinkage of the order of 4%, which gives materials which joke have a rectangular hysteresis loop.

Krympning av storleksordningen 8-30 % tillsammans med pressningstryck av storleksordningen 0,5-15 ton per kvadratcentimeter och den negativa magnetostriktionskoefficienten has materialet, som hanfor sig till sammansattningen, utgOra ocksã kannetecken for uppfinningen. Shrinkage of the order of 8-30% together with compression pressures of the order of 0.5-15 tons per square centimeter and the negative magnetostriction coefficient, the material which relates to the composition, also constitute key features of the invention.

Exempel. De foljande exemplen angivas sasom joke begransande exempel for att visa de karakteristiska egenskaperna has en del material i enlighet med uppfinningen. Example. The following examples are given as joke limiting examples to show the characteristic features of some materials in accordance with the invention.

Exempel 1. Fig. 15 visar med heldragna linjer hysteresisslingan for Ekstrom vid ett maximalt fait Hm = 2 Orsted vid en toroidkarna av ferrit med approximativt fiiljande dimensioner: Ytterdiameter: 34,7 mm Innerdiameter: 27,4 mm Hojd: 11,0 mm Utgangssammansattningen hos materialet motsvarar fOljande formel i molprocent: 50 Fe203, 40 MnO, 10 NiO. Example 1. Fig. 15 shows in solid lines the hysteresis loop for Ekstrom at a maximum fait Hm = 2 Orsted at a toroidal core of ferrite with approximately the following dimensions: Outer diameter: 34.7 mm Inner diameter: 27.4 mm Height: 11.0 mm The initial composition of the material corresponds to the following formula in mole percent: 50 Fe 2 O 3, 40 MnO, 10 NiO.

Malningen utfores under 48 timmar i en j arnkvarn med en kapacitet av 16 liter, innehdllande c:a 3 kg av blandningens c:a 6 liter vatten och c:a 20 kg stalkulor. The grinding is carried out for 48 hours in an iron mill with a capacity of 16 liters, containing about 3 kg of the mixture about 6 liters of water and about 20 kg of steel balls.

Branningen utfOres vid 1240° C under 4 timmar ren kvavgas med tillsats av 1 volymprocent syre och kylningen sker i ren kvavgas. The combustion is carried out at 1240 ° C for 4 hours of pure nitrogen with the addition of 1% by volume of oxygen and the cooling takes place in pure nitrogen.

Den linjara krympningen Or av storleksordningen 13 %. Detta material uppvisar for Mm = 10 orsted: en koercitivkraft Hem = 0,9 orsted, en flodestathet B. = 3600 gauss, en rektangularitetskoefficient /3m = BrmfBm = 0,93, Ph = 25, Pe = 30000, och für Hm = 2 orsted: en koercitivkraft Hem = 0,7orsted, en flodestathet Bm = 3000 gauss, en rektanguldritetskoefficient 13m = 0,96. The linear shrinkage Or of the order of 13%. This material shows for Mm = 10 orsted: a coercive force Hem = 0.9 orsted, a river state B. = 3600 gauss, a rectangularity coefficient / 3m = BrmfBm = 0.93, Ph = 25, Pe = 30000, and für Hm = 2 orsted: a coercive force Hem = 0.7orsted, a river density Bm = 3000 gauss, a rectangular coefficient of rectangles 13m = 0.96.

Exempel 2. Fig. 15 representerar med heldragna linjer hysteresisslingan for likstTitna vid Hm = 1,45 Orsted hanfOrande sig till ett material med utengssammansattningen i molprocent: 50 Fee0m 35 MnO, 15 NiO. Example 2. Fig. 15 represents in solid lines the hysteresis loop for equilibrium at Hm = 1.45 Orsted resulting in a material with the outer composition in mole percent: 50 Fee0m 35 MnO, 15 NiO.

Tillverkningsforfarandet Or detsamma som i exempel 1. Manufacturing procedure Or the same as in example 1.

For Hm = 10 orsted erhalles: A =84, Bm = 3500 gauss, Hem = 1,20 Orsted, flee = 0,94, Bern = 3300 gauss, Oe = 380° C. For Hm = 10 orsted are obtained: A = 84, Bm = 3500 gauss, Hem = 1.20 Orsted, flee = 0.94, Bern = 3300 gauss, Oe = 380 ° C.

Für optimala faltet H111= 1,45 Orsted erhalles: Bm = 2300 gauss, He. = 0,85 Orsted, =0,95, Rm = 0,83, Km = 16. For optimal folds H111 = 1.45 Orsted obtained: Bm = 2300 gauss, He. = 0.85 Orsted, = 0.95, Rm = 0.83, Km = 16.

Detta material kan vara lampligt fen- anvand- ling vid raknemaskiner. This material can be suitable for use with razors.

Exempel 3. Fig. 16 visar med heldragna linjer hysteresisslingan for likstrOm vid ett fait Hm = 3 orsted hanforande sig till ett material, vars ut- gangssammansattning i molprocent Or: 43,8 Fe203, 36,7 MnO, 16,6 NiO, 2,9 ZnO. Example 3. Fig. 16 shows in solid lines the hysteresis loop for direct current at a fait Hm = 3 orsted, resulting in a material whose starting composition in mole percent Or: 43.8 Fe 2 O 3, 36.7 MnO, 16.6 NiO, 2 .9 ZnO.

Tillverkningsmetoden är densamma som i exempel 1. The manufacturing method is the same as in Example 1.

For Mm = 10 orsted erhdlles: =60, Bm = 3000 gauss, Hem = 2,2 Orsted, fine = 0,83. For Mm = 10 orsted are obtained: = 60, Bm = 3000 gauss, Hem = 2.2 Orsted, fine = 0.83.

For optitnala faltet Hm. = 3 Orsted erhalles: Bm = 2400 gauss, Hem = 1,8 orsted, fim = 0,93. For optitnala fell Hm. = 3 Orsted is obtained: Bm = 2400 gauss, Hem = 1.8 orsted, fim = 0.93.

B. = 0,79. B. = 0.79.

Km = 13,7. Km = 13.7.

Exempel 4. Fig. 16 visar med streckade linjer hysteresisslingan f Or Ekstrom vid en fdltstyrka Hm = 2,55 orsted hanforande sig till ett material, vars utgangssammansattning i molprocent Or: 46,7 Fe203, 32,8 MnO, 13,5 NiO, 7 ZnO. Example 4. Fig. 16 shows in broken lines the hysteresis loop f Or Ekstrom at a field strength Hm = 2.55 orsted, which forms into a material whose starting composition in mole percent Or: 46.7 Fe 2 O 3, 32.8 MnO, 13.5 NiO, 7 ZnO.

Tillverkningsmetoden Or densamma som i exempel 1. The manufacturing method Or the same as in Example 1.

FOr Mm = 10 orsted erhalles: =80, Bm = 3000 gauss, Hem = 2,0 orsted, /3. = 0,92. For Mm = 10 orsted is obtained: = 80, Bm = 3000 gauss, Hem = 2,0 orsted, / 3. = 0.92.

FOr fdlisLyrkan Hm = 2,5 orsted erhalles: B. = 2300 gauss, Hem = 0,6 orsted, /3m = 0,91, Rm = 0,74, Km = 11,3. For fdlisLyrkan Hm = 2.5 orsted is obtained: B. = 2300 gauss, Hem = 0.6 orsted, / 3m = 0.91, Rm = 0.74, Km = 11.3.

Exempel 5. Fig. 17 visar hysteresisslingan vid Ekstrom for faltstyrkan Hm = 2 orsted hanforan- de sig till ett material, vars utgangssammansatt- ning i molprocent Or: 50 Fe203, 40 MnO, 5 NiO, 5 CuO. Example 5. Fig. 17 shows the hysteresis loop at Ekstrom for the field strength Hm = 2 orsted, resulting in a material whose starting composition in mole percent Or: 50 Fe 2 O 3, 40 MnO, 5 NiO, 5 CuO.

For H = 10 Orsted erhdlles: =80, B. = 3400 gauss, Hem = 0,8 orsted, fim = 0,94. For H = 10 Orsted erhdlles: = 80, B. = 3400 gauss, Hem = 0.8 orsted, fim = 0.94.

For faltstyrkan H. = 2 orsted erhalles: Bm = 2920 gauss, Hem = 0,7 orsted, fire = 0,97. For the fall strength H. = 2 orsted are obtained: Bm = 2920 gauss, Hem = 0.7 orsted, fire = 0.97.

Detta material kan vara lampligt for magnetiska forstarkare, dar lag koercitivkraft H. erfordras. This material may be suitable for magnetic amplifiers where low coercive force H. is required.

Exempel 6. Fig. 18 visar hysteresisslingan for 6 likstrom vid fdltstyrkan Hin = 2 Orsted hanforan- de sig till ett material, vars utgangssammansatt- Ring i molprocent är: 50 Fe203, 45 MnO, 5 CuO. Example 6. Fig. 18 shows the hysteresis loop for 6 direct currents at the field strength Hin = 2 Orsted, resulting in a material whose starting composition in mole percent is: 50 Fe 2 O 3, 45 MnO, 5 CuO.

For H = 2 Orsted erhdlles: B. = 3020 gauss, He. = 0,9 orsted, )3. = 0,94, Oe = 280° C. For H = 2 Orsted erhdlles: B. = 3020 gauss, He. = 0.9 orsted,) 3. = 0.94, Oe = 280 ° C.

TillverkningsfOrfarandet Or detsamma som i exempel 1 men glocIgningen utfores vid 1200° C. The manufacturing process is the same as in Example 1 but the glazing is carried out at 1200 ° C.

Fig. 19 representerar hysteresisslingan for detta material vid faltstyrkan 2 Orsted och vid olika behandlingstemperaturer. Fig. 19 represents the hysteresis loop for this material at the field strength 2 Orsted and at different treatment temperatures.

Fig. 20 representerar variationen av B., Hem och fl sasom funktioner av behandlingstempera- turen. Denna figur visar att variationerna av dessa parametrar dro smd. Fig. 20 represents the variation of B., Hem and fl as functions of the treatment temperature. This figure shows that the variations of these parameters drew smd.

Exempel 7. Fig. 21 visar med heldragna linjer hysteresisslingorna for ett material, vars utengs- sammansattning är: 50 Fe203, 30 MnO, 10CuO, 10 ZnO. varvid glOcIgningen utfores vid 1200° C under samma villkor som i exempel 1. Example 7. Fig. 21 shows in solid lines the hysteresis loops of a material, the initial composition of which is: 50 Fe 2 O 3, 30 MnO, 10CuO, 10 ZnO. wherein the glazing is carried out at 1200 ° C under the same conditions as in Example 1.

For optimum, dvs. faltstyrkan H. = 0,8 Orsted (inre slingan i fig. 21), uppnar rektanguldritets- koefficienten /3. vardet 0,94. For optimum, ie. field strength H. = 0.8 Orsted (inner loop in Fig. 21), reaches the rectangularity coefficient / 3. value 0.94.

B,„„ = 2360 gauss, Hem 0,5 Orsted, = 0,74, Km = 11,7, samt for en slinga for fdltstyrkan H. = 2 orsted (yttre slingan i fig. 21): Bin = 3100, 18. = 0,94, He. = 0,6 orsted. B, „„ = 2360 gauss, Hem 0,5 Orsted, = 0,74, Km = 11,7, and for a loop for the field strength H. = 2 orsted (outer loop in fig. 21): Bin = 3100, 18 = 0.94, He. = 0.6 orsted.

Exempel 8. Fig. 22 representerar med heldragna linjer hysteresisslingan tagen for ett material, vars utgAngssammansattning 40 Fe203, 40 MnO, 10 CuO, 10 ZnO, varvid glodgningen utfores vid 1200° C under samma villkor som i exempel 1. Example 8. Fig. 22 represents in solid lines the hysteresis loop taken for a material, the starting composition of which is 40 Fe 2 O 3, 40 MnO, 10 CuO, 10 ZnO, the annealing being carried out at 1200 ° C under the same conditions as in Example 1.

For en slinga vid H. = 3 Orsted erhalles: Bm = 2700 gauss, He. = 0,50 Orsted, = 0,92. For a loop at H. = 3 Orsted is obtained: Bm = 2700 gauss, He. = 0.50 Orsted, = 0.92.

Exempel 9. Fig. 23 representerar med streckade linjer en hysteresisslinga fOr ett material, vars ut- gangssammansattning i molprocent är: 45 Fe203, 5 A1203, 40 MnO, 10 CuO, varvid gliidgningen utfOres vid 1200° C under samma forhallande som i exempel 1. Example 9. Fig. 23 represents in broken lines a hysteresis loop for a material whose starting composition in mole percent is: 45 Fe 2 O 3, 5 Al 2 O 3, 40 MnO, 10 CuO, the sliding being carried out at 1200 ° C under the same conditions as in Example 1. .

For en cykel vid Mm = 3 Orsted erhalles: B. = 2500 gauss, He. = 0,80 Orsted, /3. = 0,92. For a bicycle at Mm = 3 Orsted is obtained: B. = 2500 gauss, He. = 0.80 Orsted, / 3. = 0.92.

Exempe110. Fig. 23 representerar med heldrag- na linjer en hysteresisslinga for ett material, vars utgangssammansattning i molprocent Or: 45 Fe203, 5 Cr203, 40 MnO, 10 CuO, varvid glodgningen utfores i 1200° C under samma villkor som i exempel 1. Example110. Fig. 23 represents in solid lines a hysteresis loop for a material, the starting composition of which is in mol% Or: 45 Fe 2 O 3, 5 Cr 2 O 3, 40 MnO, 10 CuO, the annealing being carried out at 1200 ° C under the same conditions as in Example 1.

For en cykel vid Hn,= 3 Orsted erhalles: B,,, = 2000 gauss, Hen,1,20 Orsted, = 0,91. For a cycle at Hn, = 3 Orsted is obtained: B ,,, = 2000 gauss, Hen, 1.20 Orsted, = 0.91.

I vart och ett av de ovan angivna exemplen kan en fjardedel av ferrioxiden ersattas genom aluminiumoxid och/eller kromoxid utan reducering av rektanguldritetskoefficienten under 0,90. In each of the above examples, a quarter of the ferric oxide can be replaced by alumina and / or chromium oxide without reducing the coefficient of rectangularity below 0.90.

Claims

Patent claim:

A ferromagnetic ceramic material having a substantially rectangular hysteresis loop and consisting of the reaction product of a mixture of oxides of solid metals, of a ferrous oxide, and oxides of divalent metals, characterized in that said mixture contains between 30 and 52 mol% in form of ferric oxide or ferric oxide together with alumina and / or chromium oxide, the proportion of alumina (odd and / or chromium oxide, if present), not exceeding one quarter of the proportion of ferric oxide, manganese oxide and at least one of the oxides nickel oxide and copper oxide, the sum of The molar proportions of manganese oxide, nickel oxide and copper oxide are between 33 and 70 per cent, where the nickel oxide is a maximum of 20 mol% and the copper oxide a maximum of 15 mol% of the total oxide content, and the sum of nickel oxide and copper oxide is between 2 mol% and half of the molar content of manganese oxide. at least one of the oxides zinc oxide and cad mium oxide, the sum of the molar proportions of ferric oxide or ferric oxide with alumina and / or chromium oxide, manganese oxide, nickel oxide and / or copper oxide and, if present, zinc cod and / or cadmium oxide being 100% without significant amounts of other metal oxides.

Ferromagnetic ceramic material according to claim 1, which does not contain nickel oxide, characterized in that the molar proportions of the oxides of hardened metals Or 40-52 per cent, the sum of the molar proportions of manganese oxide and copper oxide Or 35-55 per cent and the molar proportion of copper oxide alone Or between 2 and 15 per cent of the total oxide content.

Ferromagnetic ceramic material according to claim 1, corn does not contain copper oxide, characterized in that the sum of the molar proportions of manganese oxide and nickel oxide Or 33-70 percent and the molar proportion of nickel oxide alone Or between 2 and 20 percent of the total oxide content.

A process for producing ferromagnetic ceramic materials according to any one of the preceding claims, which comprises grinding 7 together of said oxides, pressing and then heat treatment, characterized in that the heat treatment comprises heating at a temperature between 1000 and 1350 ° C in nitrogen gas, containing between 1 and 20% by volume of oxygen, and then gentle cooling (for a period of at least 15 hours) to room temperature in an atmosphere of pure nitrogen gas. Request publications: Patents from France 1,074,864; United Kingdom 697 219.