GB1524576A - Process for preparing ferromagnetic chromium dioxide - Google Patents
Process for preparing ferromagnetic chromium dioxideInfo
- Publication number
- GB1524576A GB1524576A GB45138/76A GB4513876A GB1524576A GB 1524576 A GB1524576 A GB 1524576A GB 45138/76 A GB45138/76 A GB 45138/76A GB 4513876 A GB4513876 A GB 4513876A GB 1524576 A GB1524576 A GB 1524576A
- Authority
- GB
- United Kingdom
- Prior art keywords
- chromium dioxide
- mixture
- ferromagnetic chromium
- chromium
- modified
- 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.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/68—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent
- G11B5/70—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer
- G11B5/706—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material
- G11B5/70626—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material containing non-metallic substances
- G11B5/70636—CrO2
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G37/00—Compounds of chromium
- C01G37/02—Oxides or hydrates thereof
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G37/00—Compounds of chromium
- C01G37/02—Oxides or hydrates thereof
- C01G37/027—Chromium dioxide
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/42—Magnetic properties
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/60—Optical properties, e.g. expressed in CIELAB-values
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Hard Magnetic Materials (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Magnetic Record Carriers (AREA)
- Chemical Treatment Of Metals (AREA)
Abstract
Process for producing modified ferromagnetic chromium dioxide by thermal decomposition of chromium(III) chromate hydrate under high pressures, characterised in that a mixture of Cr2(CrO4)3.nH2O, in which n is a number from 8 to 12, with small quantities of ruthenium or tellurium or a compound thereof is prepared and the mixture is heated at temperatures of between 250 DEG C and 500 DEG C under a pressure of at least 80 atmospheres. Such a procedure makes it possible to obtain, in a simple and economical manner, a modified chromium dioxide which is characterised by a good coercive force, without significantly depressing the saturation magnetisation, with optimum granulometric properties in the form of small acicular and uniform particles. This product is used in various magnetic recording sectors (audio and video and electronic calculators).
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT28915/75A IT1045191B (en) | 1975-10-31 | 1975-10-31 | PROCEDURE FOR THE PRODUCTION OF FERROMAGNETIC CHROMIUM DIOXIDE |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1524576A true GB1524576A (en) | 1978-09-13 |
Family
ID=11224583
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB45138/76A Expired GB1524576A (en) | 1975-10-31 | 1976-10-29 | Process for preparing ferromagnetic chromium dioxide |
Country Status (17)
| Country | Link |
|---|---|
| JP (1) | JPS5274597A (en) |
| AT (1) | AT356062B (en) |
| AU (1) | AU502999B2 (en) |
| BE (1) | BE847812A (en) |
| BR (1) | BR7607234A (en) |
| CA (1) | CA1090555A (en) |
| CH (1) | CH625193A5 (en) |
| CS (1) | CS207373B2 (en) |
| DD (1) | DD127640A5 (en) |
| DE (1) | DE2648305C3 (en) |
| DK (1) | DK481376A (en) |
| ES (1) | ES452891A1 (en) |
| FR (1) | FR2329594A1 (en) |
| GB (1) | GB1524576A (en) |
| IT (1) | IT1045191B (en) |
| NL (1) | NL7611785A (en) |
| SE (1) | SE7611815L (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5030371A (en) * | 1988-11-05 | 1991-07-09 | Basf | Process for preparing acicular ferromagnetic material consisting essentially of iron-containing chromium dioxide |
| US5569409A (en) * | 1993-11-23 | 1996-10-29 | Basf Magnetics Gmbh | Finely divided acicular magnetic modified chromium dioxide |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4524008A (en) * | 1983-12-16 | 1985-06-18 | E. I. Du Pont De Nemours And Company | Controlled initiation chromium dioxide synthesis |
| DE3728453A1 (en) * | 1987-08-26 | 1989-03-09 | Basf Ag | METHOD FOR PRODUCING MODIFIED FERROMAGNETIC CHROMDIOXIDE |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2885365A (en) * | 1956-10-22 | 1959-05-05 | Du Pont | Ruthenium-modified chromium oxide ferromagnetic compositions, their pre-aration and use |
| DE1467238A1 (en) * | 1963-07-24 | 1969-01-23 | ||
| US3278263A (en) * | 1964-11-27 | 1966-10-11 | Du Pont | Ferromagnetic chromium dioxide and preparation thereof |
| CH468923A (en) * | 1967-07-21 | 1969-02-28 | Ferag Ag | Transport device for flat structures occurring in a scale formation |
| DE1802469A1 (en) * | 1968-10-11 | 1971-10-28 | Bayer Ag | Process for the production of ferromagnetic chromium dioxide |
| DE1922409A1 (en) * | 1969-05-02 | 1970-11-12 | Bayer Ag | Process for the production of ferromagnetic chromium dioxide |
| DE2022820C3 (en) * | 1970-05-11 | 1980-01-03 | Basf Ag, 6700 Ludwigshafen | Process for the production of highly coercive chromium dioxide |
| AU452489B2 (en) * | 1971-03-04 | 1974-08-16 | Montecatini Edisons. P. A | Process for preparing ferromagnetic chromium dioxide |
| JPS497198A (en) * | 1972-05-12 | 1974-01-22 | ||
| IT956230B (en) * | 1972-04-22 | 1973-10-10 | Montedison Spa | COMPOSITION OF MODIFIED FERROMAGNETIC CHROME DIOXIDE AND PREPARATION P OCES SO |
-
1975
- 1975-10-31 IT IT28915/75A patent/IT1045191B/en active
-
1976
- 1976-10-25 NL NL7611785A patent/NL7611785A/en not_active Application Discontinuation
- 1976-10-25 SE SE7611815A patent/SE7611815L/en unknown
- 1976-10-25 CH CH1351376A patent/CH625193A5/en not_active IP Right Cessation
- 1976-10-25 DK DK481376A patent/DK481376A/en not_active Application Discontinuation
- 1976-10-26 CA CA264,248A patent/CA1090555A/en not_active Expired
- 1976-10-26 DE DE2648305A patent/DE2648305C3/en not_active Expired
- 1976-10-27 BR BR7607234A patent/BR7607234A/en unknown
- 1976-10-27 CS CS766928A patent/CS207373B2/en unknown
- 1976-10-28 AT AT800476A patent/AT356062B/en not_active IP Right Cessation
- 1976-10-28 FR FR7632529A patent/FR2329594A1/en active Granted
- 1976-10-28 DD DD195502A patent/DD127640A5/xx unknown
- 1976-10-28 AU AU19118/76A patent/AU502999B2/en not_active Expired
- 1976-10-29 BE BE171938A patent/BE847812A/en not_active IP Right Cessation
- 1976-10-29 GB GB45138/76A patent/GB1524576A/en not_active Expired
- 1976-10-29 JP JP51130370A patent/JPS5274597A/en active Granted
- 1976-10-30 ES ES452891A patent/ES452891A1/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5030371A (en) * | 1988-11-05 | 1991-07-09 | Basf | Process for preparing acicular ferromagnetic material consisting essentially of iron-containing chromium dioxide |
| US5569409A (en) * | 1993-11-23 | 1996-10-29 | Basf Magnetics Gmbh | Finely divided acicular magnetic modified chromium dioxide |
Also Published As
| Publication number | Publication date |
|---|---|
| AU502999B2 (en) | 1979-08-16 |
| DE2648305B2 (en) | 1980-07-03 |
| DE2648305A1 (en) | 1977-05-12 |
| NL7611785A (en) | 1977-05-03 |
| AT356062B (en) | 1980-04-10 |
| FR2329594B1 (en) | 1981-07-31 |
| DE2648305C3 (en) | 1982-11-25 |
| BE847812A (en) | 1977-04-29 |
| JPS5722893B2 (en) | 1982-05-15 |
| BR7607234A (en) | 1977-09-13 |
| ATA800476A (en) | 1979-09-15 |
| AU1911876A (en) | 1978-05-04 |
| SE7611815L (en) | 1977-05-01 |
| DD127640A5 (en) | 1977-10-05 |
| IT1045191B (en) | 1980-05-10 |
| DK481376A (en) | 1977-05-01 |
| ES452891A1 (en) | 1977-10-16 |
| CS207373B2 (en) | 1981-07-31 |
| CA1090555A (en) | 1980-12-02 |
| JPS5274597A (en) | 1977-06-22 |
| FR2329594A1 (en) | 1977-05-27 |
| CH625193A5 (en) | 1981-09-15 |
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| GB1524576A (en) | Process for preparing ferromagnetic chromium dioxide | |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed | ||
| PCNP | Patent ceased through non-payment of renewal fee |