DK147447B - PROCEDURE FOR MAKING A MAGNETIC ARTICLE - Google Patents
PROCEDURE FOR MAKING A MAGNETIC ARTICLE Download PDFInfo
- Publication number
- DK147447B DK147447B DK417576AA DK417576A DK147447B DK 147447 B DK147447 B DK 147447B DK 417576A A DK417576A A DK 417576AA DK 417576 A DK417576 A DK 417576A DK 147447 B DK147447 B DK 147447B
- Authority
- DK
- Denmark
- Prior art keywords
- magnetite
- preformed body
- powder
- temperature
- compression
- Prior art date
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/26—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on ferrites
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/64—Burning or sintering processes
- C04B35/645—Pressure sintering
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Structural Engineering (AREA)
- Electrochemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Metallurgy (AREA)
- Inorganic Chemistry (AREA)
- Soft Magnetic Materials (AREA)
- Powder Metallurgy (AREA)
- Magnetic Ceramics (AREA)
- Hard Magnetic Materials (AREA)
- Developing Agents For Electrophotography (AREA)
- Manufacturing Cores, Coils, And Magnets (AREA)
- Thin Magnetic Films (AREA)
Description
o i U7U7 I beskrivelsen til dansk patentansøgning nr.o in U7U7 In the description of Danish patent application no.
5028/74 beskrives en fremgangsmåde til fremstilling af en genstand af magnetit (Fe^O^) med høj elektrisk ledningsevne. Denne fremgangsmåde omfatter komprimering 5 og opvarmning af magnetitpulver til en temperatur på 900-1300°C, fortrinsvis 1000-1150°C, og varmkomprimering af det nævnte opvarmede pulver ved den nævnte temperatur til dannelse af en tæt magnetitgenstand. En sådan magnetitgenstand er særlig anvendelig som elektro-10 de, f.eks. til anvendelse ved elektrolytisk korrosionsbeskyttelse af skibe og undervandskonstruktioner af jern og stål samt inden for den elektrokemiske industri.5028/74 discloses a method for producing an article of magnetite (Fe ^ O ^) with high electrical conductivity. This method comprises compressing 5 and heating magnetite powder to a temperature of 900-1300 ° C, preferably 1000-1150 ° C, and hot compressing said heated powder at said temperature to form a dense magnetite object. Such a magnetite article is particularly useful as an electrode, e.g. for use in the electrolytic corrosion protection of ships and underwater structures of iron and steel and in the electrochemical industry.
Det har vist sig, at ledningsevnen af magnetit-genstande, der er fremstillet ved den nævnte fremgangs-15 måde, kan variere på uønsket måde. Forklaringen på denne variation kan være, at en del af magnetitten er blevet omdannet til andre oxider.It has been found that the conductivity of magnetite articles produced by the aforementioned process may vary undesirably. The explanation for this variation may be that some of the magnetite has been converted to other oxides.
Det har nu ifølge den foreliggende opfindelse vist sig, at der opnås et ensartet resultat, hvis op-20 varmningen, og fortrinsvis også varmkomprimeringen, udføres i en neutral atmosfære, såsom nitrogen eller en anden gas, der er indifferent over for magnetit.It has now been found, according to the present invention, that a uniform result is obtained if the heating, and preferably also the heat compression, is carried out in a neutral atmosphere, such as nitrogen or another gas inert to magnetite.
Den foreliggende opfindelse angår derfor en fremgangsmåde til fremstilling af en magnetitgenstand ved 25 opvarmning af et præ-formet legeme af magnettitpulver til en temperatur på 900-1300°C, fortrinsvis 1000-1150°C, og varmkomprimering af det nævnte præ-formede legeme ved den nævnte temperatur til fremstilling af en tæt magnetitgenstand, hvilken fremgangsmåde er ejendommelig ved, at 30 opvarmningen, og fortrinsvis også varmkomprimeringen, udføres i en neutral atmosfære, fortrinsvis nitrogen.The present invention therefore relates to a process for producing a magnetite article by heating a preformed body of magnetite powder to a temperature of 900-1300 ° C, preferably 1000-1150 ° C, and hot compressing said preformed body at said temperature for producing a dense magnetite object which is characterized in that the heating, and preferably also the heat compression, is carried out in a neutral atmosphere, preferably nitrogen.
Magnetitpulverets partikelstørrelse er fortrinsvis under 175^u. Det første trin af fremgangsmåden ifølge opfindelsen er fortrinsvis at omdanne magnetitpulveret 35 til en art præ-formet legeme. En måde, hvorpå et sådant U7U7The particle size of the magnetite powder is preferably below 175 µm. The first step of the process according to the invention is preferably to convert the magnetite powder 35 into a kind of preformed body. One way in which such a U7U7
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2 præ-formet legeme kan fremstilles, er komprimering af pulveret til dannelse af et rålegeme. Pulveret komprimeres fortrinsvis koldt, dvs. ved normal temperatur. Det foretrækkes at anvende et midlertidigt bindemiddel, dvs. et 5 bindemiddel, der forsvinder under opvarmningen af rålegemet. Ansøgerne foretrækker at anvende polyvinylchlorid som midlertidigt bindemiddel, men der kan også anvendes andre bindemidler, såsom dekstrin. En anden måde, hvorpå et præ-formet legeme kan fremstilles, er at fylde magnetit-pulver i en åben kasse af plademetal. En tredie måde, hvorpå et præ-formet legeme kan fremstilles, er at fylde magnetitpulver i en metaldåse eller -beholder, erstatte luften i den nævnte beholder med en indifferent gas, evakuere den nævnte beholder for at fjerne det meste af 15 den indifferente gas, og lukke den nævnte evakuerede beholder. Et præ-formet legeme, der er fremstillet på denne måde, anvendes, hvis den efterfølgende varmkomprimeringsproces skal gennemføres ved isostatisk varmkomprimering.2 preformed body can be made is compression of the powder to form a crude body. The powder is preferably compressed cold, ie. at normal temperature. It is preferred to use a temporary binder, i.e. a binder which disappears during the heating of the crude body. Applicants prefer to use polyvinyl chloride as a temporary binder, but other binders such as dextrin may also be used. Another way in which a preformed body can be made is to load magnetite powder into an open box of sheet metal. A third way in which a preformed body can be made is to fill magnetite powder in a metal box or container, replace the air in said container with an inert gas, evacuate said container to remove most of the inert gas, and closing said evacuated container. A preformed body made in this way is used if the subsequent heat compression process is to be carried out by isostatic heat compression.
20 Det således fremstillede præ-formede legeme op varmes nu til en temperatur på 900-1300°C, fortrinsvis 1000-1500°C. Opvarmningen kan gennemføres i en hvilken som helst ønsket ovntype. En neutral gas føres til ovnen for at forhindre luften i at komme i kontakt med magne-25 titten. Den neutrale gas er som nævnt fortrinsvis nitrogen, men der kan anvendes en hvilken som helst anden gas, der er indifferent over for magnetit, såsom argon eller andre ædelgasser.The preformed body thus produced is now heated to a temperature of 900-1300 ° C, preferably 1000-1500 ° C. The heating can be carried out in any desired oven type. A neutral gas is fed to the furnace to prevent the air from contacting the magnetite. The neutral gas, as mentioned, is preferably nitrogen, but any other gas inert to magnetite can be used, such as argon or other noble gases.
Det opvarmede præformede legeme overføres nu til 30 et komprimeringsapparat så hurtigt som muligt for at undgå noget som helst betydende temperaturfald. Det komprimeres nu til dannelse af et i det væsentlige tæt magnetit-legeme. Komprimeringstrykket skal være mindst 100 MPa (Megapascal). Et tryk højere end 600 MPa er sædvanligvis 35 ikke nødvendigt. Det foretrækkes at gennemføre varmkomprimeringsprocessen ved hjælp af et gængs komprimerings- U7447The heated preformed body is now transferred to a compressor as quickly as possible to avoid any significant temperature drop. It is now compressed to form a substantially dense magnetite body. The compression pressure must be at least 100 MPa (Megapascal). A pressure higher than 600 MPa is usually not required. It is preferred to carry out the heat compression process using a conventional compression method U7447
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3 værktøj. Værktøjets temperatur holdes fortrinsvis under 500°C for at formindske sliddet af dette og for at forøge komprimeringshastigheden. Det har vist sig, at en komprimeringstid på mindre end 1 sekund er tilstrække-5 lig til fremstilling af en tæt magnetitgenstand. Fortrinsvis blæses en neutral gas mod komprimeringsværktøjet for at forhindre kontakt mellem magnetitten og luften. I stedet for at anvende et konventionelt komprimeringsværktøj kan magnetitten også varmkomprimeres ved 10 hjælp af et isostatisk komprimeringsapparat. I dette tilfælde skal magnetitpulveret anbringes i en lukket beholder, som ovenfor beskrevet. I det isostatiske komprimeringsapparat opvarmes og komprimeres det præ-formede legeme samtidig.3 tools. Preferably, the temperature of the tool is kept below 500 ° C to reduce the wear thereof and to increase the compression rate. It has been found that a compaction time of less than 1 second is sufficient to produce a dense magnetite article. Preferably, a neutral gas is blown against the compression tool to prevent contact between the magnetite and the air. Instead of using a conventional compression tool, the magnetite can also be heat-compressed by means of an isostatic compression apparatus. In this case, the magnetite powder should be placed in a sealed container as described above. In the isostatic compression apparatus, the preformed body is heated and compressed simultaneously.
15 Hvis der er anvendt en metaldåse eller -beholder ved fremstillingen af det præ-formede legeme, kan det nu være ønskeligt at fjerne det metalliske overfladelag fra den varmkomprimerede magnetitgenstand. Dette overfladelag kan fjernes ved mekaniske metoder, ved kemisk opløs-20 ning eller ved termisk smeltning.If a metal can or container has been used in the manufacture of the preformed body, it may now be desirable to remove the metallic surface layer from the hot-compressed magnetite article. This surface layer can be removed by mechanical methods, by chemical solution or by thermal melting.
Hvis magnetitgenstanden skal anvendes som elektrode, kan det være ønskeligt at fastgøre én eller flere kobberplader til elektrodens overflade, f.eks. for at lette fastgørelsen af elektriske kabler. Sådanne kobber-25 plader kan fastgøres ved følgende metode.If the magnetite object is to be used as an electrode, it may be desirable to attach one or more copper plates to the surface of the electrode, e.g. to facilitate the attachment of electrical cables. Such copper sheets can be attached by the following method.
Hvis det præformede legeme består af koldkompri-meret magnetitpulver, anbringes en tynd kobberplade enten i komprimeringsværktøjet, før det opvarmede præformede legeme indsættes deri, eller ovenpå eller omkring magne-30 titlegemet selv før eller umiddelbart efter dets opvarmning. Under varmkomprimeringsprocessen hæfter kobberpla-' den til magnetitlegemet og danner et tætsluttende kobber lag. Hvis det præformede legeme består af en plademetal-beholder fyldt med magnetitpulver, kan beholderen være 35 fremstillet af kobber.If the preformed body is comprised of cold-compressed magnetite powder, a thin copper plate is placed either in the compression tool before the heated preformed body is inserted therein, or on top or around the magnetic body even before or immediately after its heating. During the heat compression process, the copper plate adheres to the magnetite body to form a tightly sealed copper layer. If the preformed body consists of a sheet metal container filled with magnetite powder, the container may be made of copper.
44
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U7447U7447
EksempelExample
Magnetitpulver med en partikelstørrelse under 300^,u, der indeholder 1 vægtprocent polyvinylchlorid som midlertidigt bindemiddel, komprimeres til stang-5 formede præ-formede legemer i et komprimeringsværktøj af den type, der anvendes inden for den keramiske og pulvermetallurgiske industri. Værktøjet forvarmes til en temperatur på 250°C. De præ-formede legemer opvarmes i en ovn til 1150°C. Der blæses kontinuerligt ni-10 trogen ind i ovnen for at skabe en neutral atmosfære.Magnetite powder having a particle size less than 300 µm, containing 1% by weight of polyvinyl chloride as a temporary binder, is compressed into rod-shaped preformed bodies in a compaction tool of the type used in the ceramic and powder metallurgical industry. The tool is preheated to a temperature of 250 ° C. The preformed bodies are heated in an oven to 1150 ° C. Nine-10 troughs are continuously blown into the oven to create a neutral atmosphere.
De opvarmede præ-formede legemer overføres hurtigt til et komprimeringsværktøj, der ligner det ovenfor omtalte, og komprimeres ved et tryk på 600 MPa. De fremstillede genstande er tætte og har en særdeles god elek-15 trisk ledningsevne, der forbliver konstant under fremstillingen af et stort antal genstande.The heated preformed bodies are quickly transferred to a compression tool similar to the one mentioned above and compressed at a pressure of 600 MPa. The manufactured articles are dense and have a very good electrical conductivity which remains constant during the manufacture of a large number of articles.
Claims (1)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE7510541 | 1975-09-19 | ||
| SE7510541 | 1975-09-19 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| DK417576A DK417576A (en) | 1977-03-20 |
| DK147447B true DK147447B (en) | 1984-08-13 |
| DK147447C DK147447C (en) | 1985-02-25 |
Family
ID=20325605
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| DK417576A DK147447C (en) | 1975-09-19 | 1976-09-16 | PROCEDURE FOR MAKING A MAGNETIC ARTICLE |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS5238515A (en) |
| DD (1) | DD126273A5 (en) |
| DE (1) | DE2635851C3 (en) |
| DK (1) | DK147447C (en) |
| FR (1) | FR2324591A2 (en) |
| GB (1) | GB1499229A (en) |
| IT (1) | IT1065810B (en) |
| NL (1) | NL7609566A (en) |
| NO (1) | NO143304C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IL81512A0 (en) * | 1986-02-12 | 1987-09-16 | Dow Chemical Co | Novel method for producing ceramic bodies |
| JP5276837B2 (en) * | 2007-12-17 | 2013-08-28 | 株式会社神戸製鋼所 | Method for producing magnetite bulk material |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2106793A5 (en) * | 1970-09-24 | 1972-05-05 | Corning Glass Works | High temperature gas pressing ceramics and - metals |
| US3732056A (en) * | 1971-09-01 | 1973-05-08 | Gen Motors Corp | Apparatus for hot pressing oxide ceramics in a controlled oxygen atmosphere |
| JPS5546991B2 (en) * | 1974-10-21 | 1980-11-27 |
-
1976
- 1976-08-10 DE DE2635851A patent/DE2635851C3/en not_active Expired
- 1976-08-27 NL NL7609566A patent/NL7609566A/en not_active Application Discontinuation
- 1976-08-31 IT IT26714/76A patent/IT1065810B/en active
- 1976-09-06 NO NO763055A patent/NO143304C/en unknown
- 1976-09-09 GB GB37489/76A patent/GB1499229A/en not_active Expired
- 1976-09-16 DK DK417576A patent/DK147447C/en not_active IP Right Cessation
- 1976-09-17 FR FR7628107A patent/FR2324591A2/en active Granted
- 1976-09-17 DD DD194851A patent/DD126273A5/xx unknown
- 1976-09-17 JP JP51110920A patent/JPS5238515A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| FR2324591A2 (en) | 1977-04-15 |
| GB1499229A (en) | 1978-01-25 |
| DE2635851C3 (en) | 1979-04-12 |
| DE2635851A1 (en) | 1977-03-24 |
| FR2324591B2 (en) | 1979-04-20 |
| NO143304C (en) | 1981-01-14 |
| NO763055L (en) | 1977-03-22 |
| NL7609566A (en) | 1977-03-22 |
| IT1065810B (en) | 1985-03-04 |
| DK417576A (en) | 1977-03-20 |
| DK147447C (en) | 1985-02-25 |
| JPS5238515A (en) | 1977-03-25 |
| DD126273A5 (en) | 1977-07-06 |
| NO143304B (en) | 1980-10-06 |
| DE2635851B2 (en) | 1978-07-20 |
| JPS573628B2 (en) | 1982-01-22 |
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| PBP | Patent lapsed |