DE1291028B - Process for the production of a thin, electrically insulating surface layer on iron powder for use in magnetic cores - Google Patents
Process for the production of a thin, electrically insulating surface layer on iron powder for use in magnetic coresInfo
- Publication number
- DE1291028B DE1291028B DEN21993A DEN0021993A DE1291028B DE 1291028 B DE1291028 B DE 1291028B DE N21993 A DEN21993 A DE N21993A DE N0021993 A DEN0021993 A DE N0021993A DE 1291028 B DE1291028 B DE 1291028B
- Authority
- DE
- Germany
- Prior art keywords
- iron powder
- solution
- acid
- phosphoric acid
- surface layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
- H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
- H01F1/16—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of sheets
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/14—Treatment of metallic powder
- B22F1/145—Chemical treatment, e.g. passivation or decarburisation
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
- C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
- C23C22/24—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing hexavalent chromium compounds
- C23C22/33—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing hexavalent chromium compounds containing also phosphates
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
- H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
- H01F1/20—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder
- H01F1/22—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
- H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
- H01F1/20—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder
- H01F1/22—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together
- H01F1/24—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together the particles being insulated
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
- Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
- Y10T428/2991—Coated
Description
Die Erfindung bezieht sich auf ein Verfahren zur Herstellung einer dünnen, elektrisch isolierenden Oberflächenschicht auf Eisenpulver zur Verwendung in Magnetkernen, beispielsweise Dämpfungselementen, durch Behandeln des Eisenpulvers mit einer phosphorsauren Lösung, anschließendes Waschen und Trocknen.The invention relates to a method of making a thin, electrically insulating surface layer on iron powder for use in magnetic cores, for example damping elements, by treating the iron powder with a phosphoric acid solution, subsequent washing and drying.
Bisher wurde es als schwierig angesehen, die die Eisenpulverteilchen umgebende Phosphatisolierhaut so gleichmäßig ausfallen zu lassen, wie es im fabrikatorischen Verfahren erwünscht ist. Man war der Auffassung, daß sich durch den chemischen Angriff die Dicke und die Gleichmäßigkeit dieser isolierenden Deckhaut schwer genau einregeln ließ, weshalb verhältnismäßig dicke Phosphatschichten aufzubringen waren, um eine ausreichend hohe Isolation zu erreichen. Als Ausweg wurde in diesem Zusammenhang ein Verfahren beschrieben, nach dem Nichteisen-Phosphatteilchen ohne chemische Reaktion auf die Eisenpulverteilchen aufgebracht werden, wodurch sich Deckschichten ohne feste Bindung mit dem Eisen bilden, die in brauchbar geringer Stärke nur eine unvollkommene Isolierung ergeben.So far it has been considered difficult to pick up the iron powder particles to let the surrounding phosphate insulating skin turn out as evenly as it is in the manufacturing process Procedure is desired. It was believed that the chemical attack It is difficult to precisely regulate the thickness and evenness of this insulating cover skin left, which is why relatively thick phosphate layers had to be applied to a to achieve a sufficiently high level of isolation. The way out was in this regard described a method according to which non-ferrous phosphate particles without chemical reaction are applied to the iron powder particles, creating top layers without Form a firm bond with the iron, which in usable weakness is only an imperfect one Isolation.
Außerdem ist es bekannt, Bleche mit einer relativ dicken Phosphatschicht zu überziehen, die zusätzlich ein anorganisches Pigment, z. B. Cr,0.3, enthält und nach der Aufbringung eingebrannt wird. Man hat auf Blechen Phosphatschichten auch aus alkalischen Phosphatlösungen erzeugt. Schließlich wurden auch schon korrosionshindernde überzüge auf gegebenenfalls mit einem anderen Metall überzogene Eisenbleche aus einer Lösung mit etwa 5% Phosphorsäure und 311/o Chromsäure aufgebracht. Derartig hohe Säurekonzentrationen führen in relativ kurzer Zeit zu verhältnismäßig dicken, aber nicht vollkommen dichten überzügen, die keine guten isolierenden Eigenschaften haben.It is also known to have sheets with a relatively thick phosphate layer to be coated, which additionally contains an inorganic pigment, e.g. B. Cr, 0.3, contains and is baked after application. There are also phosphate layers on sheet metal generated from alkaline phosphate solutions. After all, they were already anti-corrosive coatings on iron sheets optionally coated with another metal a solution with about 5% phosphoric acid and 311 / o chromic acid applied. Such high acid concentrations lead to relatively thick, but not completely impermeable coatings that do not have good insulating properties to have.
Der Erfindung liegt die Aufgabe zugrunde, das eingangs genannte Verfahren zur Herstellung einer dünnen, elektrisch isolierenden Oberflächenschicht auf Eisenpulver derart auszubilden, daß die Oberflächenschicht vollkommen dicht ist, am Eisenpulver gut haftet und dem zu einer kompakten Masse geformten Eisenpulver schon in dünner Schicht einen spezifischen Widerstand von wenigstens 1 Megohm - cm verleiht.The invention is based on the object of the aforementioned method for the production of a thin, electrically insulating surface layer on iron powder to be designed in such a way that the surface layer is completely impervious to the iron powder adheres well and the iron powder, which is formed into a compact mass, is already thinner Layer gives a resistivity of at least 1 megohm-cm.
Diese Aufgabe wird erfindungsgemäß im wesentlichen dadurch gelöst, daß Eisenpulver einer Teilchengröße von nicht mehr als etwa 10 bum mit einer Gesamtmenge von 0,5 bis 2,5 % des Eisenpulvergewichts an Phosphorsäure und einer Gesamtmenge von 0,5 bis 2,511/o des Eisenpulvergewichts an Chromsäure in einer Lösung von mindestens 21 Wasser je 1 kg Eisenpulver in der Weise behandelt wird, daß man die Mischung ausreichend 'rührt, um die Teilchen in der Flüssigkeit suspendiert zu halten, und die Säurezugabe zur Eisenpulversuspension über die Behandlungsdauer derart verteilt, daß die Konzentration dieser Säure in der Lösung 0,1% nicht überschreitet.According to the invention, this object is essentially achieved by that iron powder having a particle size of not more than about 10 µm in total from 0.5 to 2.5% of the iron powder weight of phosphoric acid and a total amount from 0.5 to 2.511 / o of the iron powder weight of chromic acid in a solution of at least 21 water per 1 kg of iron powder is treated in such a way that the mixture sufficient stirring to keep the particles suspended in the liquid, and the addition of acid to the iron powder suspension is distributed over the duration of the treatment in such a way that that the concentration of this acid in the solution does not exceed 0.1%.
Die Anwesenheit von insgesamt wenigstens etwa 1/2 Gewichtsprozent Chromsäure trägt zur Bildung eines stabilen und weitgehend kontinuierlichen Eisenphosphatüberzuges bei, und durch Begrenzung der verwendeten Phosphorsäuremenge, d. h. ebenfalls insgesamt wenigstens etwa 1/2 Gewichtsprozent des zu behandelnden Eisenpulvers, kann ein sehr dünner, jedoch einen hohen Widerstand aufweisender Überzug gebildet werden, der die behandelten Teilchen vorwiegend als metallisches Eisen zurückläßt, das jedoch als verdichtete Masse einen sehr hohen elektrischen Widerstand aufweist.The presence of at least about 1/2 weight percent total Chromic acid contributes to the formation of a stable and largely continuous iron phosphate coating with, and by limiting the amount of phosphoric acid used, d. H. also in total at least about 1/2 percent by weight of the iron powder to be treated can be a very thin but high resistance coating can be formed, the but leaves the treated particles predominantly as metallic iron as a compacted mass has a very high electrical resistance.
Die Behandlung wird schnell durchgeführt, indem man das Eisenpulver in einer verdünnten Lösung, welche Phosphorsäure und Chromsäure enthält, suspendiert. Die Anwesenheit der Chromsäure ist anfangs nicht notwendig, wenn sich bei der Behandlung von relativ unaktivem Eisenpulver ergibt, daß ihre spätere Zugabe zweckmäßiger ist.The treatment is done quickly by getting the iron powder suspended in a dilute solution containing phosphoric acid and chromic acid. The presence of chromic acid is initially unnecessary when used in the treatment of relatively inactive iron powder shows that it is more appropriate to add it later.
Die Dicke des gebildeten widerstandsfähigen überzuges ist von der Menge und Konzentration der verwendeten Säuren in den genannten Grenzen abhängig, die daher normalerweise auf die Beträge beschränkt werden, die zur Herstellung eines Pulvers mit dem gewünschten Wert des spezifischen Widerstandes notwendig sind.The thickness of the resistant coating formed is of the The amount and concentration of the acids used depends on the specified limits, which are therefore normally limited to the amounts needed to produce a Powder with the desired value of the specific resistance are necessary.
Das Volumen der Lösung muß ausreichend sein, um das Eisenpulver schnell durch kräftiges Rühren zu suspendieren und einen geeigneten Verdünnungsgrad für die Reaktion mit der Phosphor- und Chromsäure zu ergeben. Daher verwendet man wenigstens 21 Wasser je 1 kg Eisenpulver. Um eine zu hohe Säurekonzentration während der überzugsbildung zu vermeiden, werden die Säuren nach und nach zugefügt, wobei die Konzentration jeder der Säuren während dieser Periode 0,111/o oder weniger, vorzugsweise etwa 0,0511/o oder weniger ist und die Einwirkung durch Erschöpfen der Säurelösung beendet wird.The volume of the solution must be sufficient to remove the iron powder quickly suspend by vigorous stirring and a suitable degree of dilution for to give the reaction with the phosphoric and chromic acids. So at least one uses 21 water per 1 kg of iron powder. Too high an acid concentration during the formation of the coating to avoid the acids are added gradually, increasing the concentration each of the acids during this period 0.111 / o or less, preferably about Is 0.0511 / o or less and the exposure is terminated by exhausting the acid solution will.
Der Prozeß kann durch Erhöhung der Lösungstemperatur gefördert werden, zweckmäßig durch Erwärmen auf 50 bis 80° C. Er sollte mit Materialien hoher Reinheit, die möglich wenig Verunreinigungen enthalten, durchgeführt werden.The process can be promoted by increasing the solution temperature, expediently by heating to 50 to 80 ° C. It should be made with materials of high purity, which contain as few impurities as possible can be carried out.
Ein Eisenpulver, das so behandelt werden kann, daß es einen sehr hohen spezifischen Widerstand (über 100 Megohm - cm) erhält, besteht aus im wesentlichen kugelförmigen Teilchen mit einer Größe von 1 bis 10 [m, wie z. B. das aus Eisencarbonyl gewonnene Carbonyleisenpulver.An iron powder that can be treated to be very high resistivity (over 100 megohm - cm) consists essentially of spherical particles with a size of 1 to 10 [m, such as. B. that of iron carbonyl obtained carbonyl iron powder.
Die Behandlung eines 2-kg-Ansatzes von Eisenpulver wird nach den folgenden allgemeinen Richtlinien durchgeführt.Treatment of a 2 kg batch of iron powder is as follows general guidelines carried out.
Das Eisenpulver wird in etwa 41 Wasser bei 50 bis 80° C kräftig gerührt. 1 1 einer Lösung, die 20 g Chromsäure und 20 g Phosphorsäure enthält, wird langsam während einer Dauer von 10 bis 30 Minuten zu der gerührten und bei 50 bis 80° C gehaltenen Lösung hinzugefügt. Am Schluß wird das Pulver von der Flüssigkeit abgetrennt, sorgfältig gewaschen und getrocknet.The iron powder is stirred vigorously in about 41% water at 50 to 80 ° C. 1 liter of a solution containing 20 g of chromic acid and 20 g of phosphoric acid is slow for a period of 10 to 30 minutes to the stirred and at 50 to 80 ° C held solution added. At the end the powder is separated from the liquid, carefully washed and dried.
Dickere Isolierüberzüge werden durch entsprechende Erhöhung der Mengen an verwendeten Säuren sowie durch Verlängerung der Behandlungsdauer hergestellt.Thicker insulating coatings are obtained by increasing the quantities accordingly of acids used as well as by extending the duration of the treatment.
Das Verhalten des Eisenpulvers hinsichtlich der Bildung des Oberflächenüberzugs durch diese Behandlung hängt von der Reinheit des Pulvers ab, insbesondere bei Carbonyleisenpulvern von deren Kohlenstoffgehalt. Ein Eisen mit niederem Kohlenstoffgehalt ist im allgemeinen weniger reaktionsfreudig als ein Eisen mit hohem Kohlenstoffgehalt. Das folgende Verfahren für ein Carbonyleisen mit geringem Kohlenstoffgehalt, das weniger als 0,050/0C enthält, ist als Beispiel wiedergegeben.The behavior of the iron powder with regard to the formation of the surface coating this treatment depends on the purity of the powder, especially in the case of carbonyl iron powders of their carbon content. A low carbon iron is generally less reactive than a high carbon iron. The following Process for a low carbon carbonyl iron that is less than 0.050 / 0C is given as an example.
300 g Eisenpulver werden unter kräftigem Rühren bei 65 bis 70'i' C zu 400 ml destilliertem Wasser gegeben. Dann werden 100 ml einer Lösung, die 1,3 ml Phosphorsäure (Dichte 1,75) enthält, zu der gerührten Suspension hinzugefügt, jeweils 10 ml in Intervallen von je einer Minute. Darauf gibt man 100 ml einer Lösung, die 2 g Chromsäure enthält, hinzu, wieder jeweils 10 ml in Intervallen von je einer Minute. Das Rühren wird weitere 5 Minuten fortgesetzt und die Temperatur des Gemisches durchweg bei 65 bis 70" C gehalten.300 g iron powder are stirred vigorously at 65 to 70'i 'C added to 400 ml of distilled water. Then 100 ml become one Solution containing 1.3 ml of phosphoric acid (density 1.75) to the stirred suspension added, 10 ml each at one minute intervals. You give 100 on that ml of a solution containing 2 g of chromic acid is added, again 10 ml at intervals of one minute each. Stirring is continued and temperature is continued for an additional 5 minutes the mixture was kept at 65 to 70 "C throughout.
Dann werden unter sorgfältigem Rühren 500 ml destilliertes Wasser zugefügt. Anschließend läßt man das Pulver absetzen und dekantiert die Flüssigkeit. Das Waschen und das Abtrennen der Flüssigkeit werden zwei- oder dreimal wiederholt, bis die dekantierte Flüssigkeit frei von gelber Färbung ist und die löslichen Chemikalien ausgewaschen sind.Then, with careful stirring, 500 ml of distilled water are added added. The powder is then allowed to settle and the liquid is decanted. Washing and separating the liquid are repeated two or three times, until the decanted liquid is free of yellow color and the soluble chemicals are washed out.
Das Pulver wird dann in 500 ml Methylalkohol gerührt, abfiltriert (unter Verwendung eines Büchnertrichters und Whatmanfilters, Papier Nr. 541), erneut mit 200 ml Methylalkohol gewaschen und schließlich ausgebreitet und in einem Ofen bei etwa 80° C 1. Stunde lang getrocknet.The powder is then stirred in 500 ml of methyl alcohol and filtered off (using a Buchner funnel and Whatman filter, paper # 541), again washed with 200 ml of methyl alcohol and finally spread out and placed in an oven dried at about 80 ° C for 1 hour.
Wenn das Eisenpulver einen höheren Kohlenstoffgehalt hat, z. B. 0,6 % C, kann der Prozeß vereinfacht werden. An Stelle der Zugabe einer Phosphorsäurelösung mit anschließender Zugabe einer Chromsäurelösung werden 100 ml einer kombinierten Lösung, die 1,3 ml Phosphorsäure (Dichte 1,75) und 2 g Chromsäure enthält, zugefügt, und zwar jeweils 10 ml in Abständen von 2 Minuten, so daß die Lösung innerhalb von 20 Minuten zugefügt ist.If the iron powder has a higher carbon content, e.g. B. 0.6 % C, the process can be simplified. Instead of adding a phosphoric acid solution with the subsequent addition of a chromic acid solution, 100 ml of a combined Solution containing 1.3 ml of phosphoric acid (density 1.75) and 2 g of chromic acid added, in each case 10 ml at intervals of 2 minutes, so that the solution within 20 minutes is added.
Als Ergebnis dieser Behandlung bekommt das Eisenpulver mit hohem Kohlenstoffgehalt eine dunkle Khakifarbe, während Pulver mit niederem Kohlenstoffgehalt dunkelgrau sind und nur wenig ihre Farbe ändern.As a result of this treatment, the iron powder becomes high in carbon a dark khaki color, while low carbon powders are dark gray and change their color only a little.
Gut behandelte Carbonyleisenpulver (durchschnittliche Teilchengröße 3 bis 7 jm) von sowohl hohem als geringem Kohlenstoffgehalt sollten noch einen hohen Anteil ihres Metallgehalts beibehalten (über 95 %), während der Überzug auf den Eisenteilchen ausreicht, um einen Gesamtphosphatgehalt von 0,7 bis 1.,0% und einen Chromgehalt von 0,1 bis 0,5% zu gewährleisten. Die Dicke des Überzuges liegt wahrscheinlich in der Größenordnung von 0,05 [m.Well treated carbonyl iron powder (average particle size 3 to 7 µm) of both high and low carbon content should still have a high Maintain percentage of their metal content (over 95%) while coating on the Iron particles are sufficient to have a total phosphate content of 0.7 to 1., 0% and a Ensure a chromium content of 0.1 to 0.5%. The thickness of the coating is likely of the order of 0.05 [m.
Das wichtigste Merkmal des erfindungsgemäß behandelten Carbonyleisenpulvers ist der hohe Wert des elektrischen Widerstandes. Für verdichtete Pulver von sowohl hohem als auch geringem Kohlenstoffgehalt betragen die gemessenen spezifischen Widerstände über 100 Megohm - cm.The most important feature of the carbonyl iron powder treated according to the invention is the high value of the electrical resistance. For compacted powders of both high as well as low carbon content are the measured resistivities over 100 megohms - cm.
Claims (3)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB31348/61A GB1046241A (en) | 1961-08-31 | 1961-08-31 | Improvements in the production of iron powder having high electrical resistivity |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| DE1291028B true DE1291028B (en) | 1969-03-20 |
Family
ID=10321790
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| DEN21993A Pending DE1291028B (en) | 1961-08-31 | 1962-08-22 | Process for the production of a thin, electrically insulating surface layer on iron powder for use in magnetic cores |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US3245841A (en) |
| DE (1) | DE1291028B (en) |
| GB (1) | GB1046241A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3439397A1 (en) * | 1984-10-27 | 1986-04-30 | Vacuumschmelze Gmbh, 6450 Hanau | Process for the production of a soft-magnetic body by powder metallurgy |
| DE3907090C2 (en) * | 1989-03-04 | 2001-07-26 | Vacuumschmelze Gmbh | Process for the powder metallurgical production of a soft magnetic body |
| US6348265B1 (en) | 1996-02-23 | 2002-02-19 | Höganäs Ab | Phosphate coated iron powder and method for the manufacturing thereof |
| US6562458B2 (en) | 2000-02-11 | 2003-05-13 | Höganäs Ab | Iron powder and method for the preparation thereof |
| DE10150830B4 (en) * | 2000-10-16 | 2012-06-06 | Aisin Seiki K.K. | Soft magnetic metal powder, a treatment method thereof, and a soft magnetic molding method manufacturing method |
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| US4601753A (en) * | 1983-05-05 | 1986-07-22 | General Electric Company | Powdered iron core magnetic devices |
| US4601765A (en) * | 1983-05-05 | 1986-07-22 | General Electric Company | Powdered iron core magnetic devices |
| US5982073A (en) * | 1997-12-16 | 1999-11-09 | Materials Innovation, Inc. | Low core loss, well-bonded soft magnetic parts |
| SE0100236D0 (en) | 2001-01-26 | 2001-01-26 | Hoeganaes Ab | Compressed soft magnetic materials |
| SE0102103D0 (en) | 2001-06-13 | 2001-06-13 | Hoeganaes Ab | High density soft magnetic products and method for the preparation thereof |
| JP2004197212A (en) * | 2002-10-21 | 2004-07-15 | Aisin Seiki Co Ltd | Soft magnetic molding, method of producing soft magnetic molding, and soft magnetic powder material |
| US20050016658A1 (en) * | 2003-07-24 | 2005-01-27 | Thangavelu Asokan | Composite coatings for ground wall insulation in motors, method of manufacture thereof and articles derived therefrom |
| US20050019558A1 (en) * | 2003-07-24 | 2005-01-27 | Amitabh Verma | Coated ferromagnetic particles, method of manufacturing and composite magnetic articles derived therefrom |
| US7803457B2 (en) * | 2003-12-29 | 2010-09-28 | General Electric Company | Composite coatings for groundwall insulation, method of manufacture thereof and articles derived therefrom |
| CN103700460B (en) * | 2013-09-03 | 2016-04-20 | 横店集团东磁股份有限公司 | A kind of low-loss is without the preparation method of heat ageing ferrocart core |
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| US2144425A (en) * | 1936-12-09 | 1939-01-17 | Sterling Varnish Company | Insulating composition |
| FR841684A (en) * | 1938-08-03 | 1939-05-24 | Eisen Und Hu Ttenwerke Ag | Manufacturing process of silicon sheets for transformers |
| DE703669C (en) * | 1936-04-30 | 1941-03-13 | Philips Patentverwaltung | Magnetic core and method of making the material for the same |
| FR866359A (en) * | 1940-03-29 | 1941-08-04 | Parker Ste Continentale | Corrosion resistant ferrous metal sheet |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1850181A (en) * | 1929-02-08 | 1932-03-22 | Automatic Telephone Mfg Co Ltd | Magnet core |
| US1982690A (en) * | 1929-08-26 | 1934-12-04 | Johnson Lab Inc | Selective radio circuit |
| US2306198A (en) * | 1937-04-26 | 1942-12-22 | Verweij Evert Johannes Willem | Production of magnetic material |
| FR837210A (en) * | 1937-04-30 | 1939-02-06 | Lignes Telegraph Telephon | Method of isolating magnetic powders for compressed cores |
| BE462834A (en) * | 1944-04-19 | |||
| BE463593A (en) * | 1944-11-14 | |||
| US2634225A (en) * | 1950-06-21 | 1953-04-07 | American Chem Paint Co | Ammonium chromate rinse for phosphate coated metal surfaces |
| US2783208A (en) * | 1954-01-04 | 1957-02-26 | Rca Corp | Powdered iron magnetic core materials |
-
1961
- 1961-08-31 GB GB31348/61A patent/GB1046241A/en not_active Expired
-
1962
- 1962-08-15 US US216986A patent/US3245841A/en not_active Expired - Lifetime
- 1962-08-22 DE DEN21993A patent/DE1291028B/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE703669C (en) * | 1936-04-30 | 1941-03-13 | Philips Patentverwaltung | Magnetic core and method of making the material for the same |
| US2144425A (en) * | 1936-12-09 | 1939-01-17 | Sterling Varnish Company | Insulating composition |
| FR841684A (en) * | 1938-08-03 | 1939-05-24 | Eisen Und Hu Ttenwerke Ag | Manufacturing process of silicon sheets for transformers |
| FR866359A (en) * | 1940-03-29 | 1941-08-04 | Parker Ste Continentale | Corrosion resistant ferrous metal sheet |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3439397A1 (en) * | 1984-10-27 | 1986-04-30 | Vacuumschmelze Gmbh, 6450 Hanau | Process for the production of a soft-magnetic body by powder metallurgy |
| DE3907090C2 (en) * | 1989-03-04 | 2001-07-26 | Vacuumschmelze Gmbh | Process for the powder metallurgical production of a soft magnetic body |
| US6348265B1 (en) | 1996-02-23 | 2002-02-19 | Höganäs Ab | Phosphate coated iron powder and method for the manufacturing thereof |
| US6562458B2 (en) | 2000-02-11 | 2003-05-13 | Höganäs Ab | Iron powder and method for the preparation thereof |
| DE10150830B4 (en) * | 2000-10-16 | 2012-06-06 | Aisin Seiki K.K. | Soft magnetic metal powder, a treatment method thereof, and a soft magnetic molding method manufacturing method |
Also Published As
| Publication number | Publication date |
|---|---|
| GB1046241A (en) | 1966-10-19 |
| US3245841A (en) | 1966-04-12 |
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