GB722175A - Improvements in or relating to the production of magnetisable material - Google Patents
Improvements in or relating to the production of magnetisable materialInfo
- Publication number
- GB722175A GB722175A GB2728349A GB2728349A GB722175A GB 722175 A GB722175 A GB 722175A GB 2728349 A GB2728349 A GB 2728349A GB 2728349 A GB2728349 A GB 2728349A GB 722175 A GB722175 A GB 722175A
- Authority
- GB
- United Kingdom
- Prior art keywords
- pot
- hydrogen
- water
- ferric oxide
- heating
- 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
- G11B5/70642—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 iron oxides
- G11B5/70678—Ferrites
- G11B5/70684—Ferro-ferrioxydes
Landscapes
- Hard Magnetic Materials (AREA)
Abstract
<PICT:0722175/III/1> Black ferroferric oxide having a coercive force of about 250-325 oersteds and a remanence of about 3,500 gaus or higher and suitable for making a magnetic sound recorder-reproducer tape, is prepared by heating finely divided yellow, hydrated ferric oxide to about 400-450 DEG C. for about 60-120 minutes and, whilst heating, applying or reducing gas such as hydrogen or carbon monoxide under pressure, e.g. at 25-35 lbs./sq. in. above atmospheric. The ferric oxide used may be obtained by precipitation or by heating ferrous sulphate heptahydrate at 600-700 DEG C. A suitable reduction furnace comprises a pot 20 mounted on rollers 11 and heated electrically by coil 12. The pot may be arranged to rotate. A valved pipe 35 extends through the non-heated portion of the pot, and a baffle wall 21. The furnace is first heated to 600-700 DEG C., and the pot with ferric oxide therein, bearing, say, a volume ratio of 1:50 with the void space, is then placed in position. Cover 30 is bolted on, and moisture escapes through valved pipe 25. Thereupon, the valve is closed and hydrogen under pressure admitted through pipe 35 for the prescribed period. Evolved steam condenses on the water-cooled end cover 30. Alternatively, water-absorbing material, such as silica gel or alumina, may be put into the pot. The pot when removed may be allowed to cool, or quenched in water. If the reduction process is carried too far, whereby a spontaneously-ignitable product is formed, it may be reversed by replacing the hydrogen by steam.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2728349A GB722175A (en) | 1949-10-24 | 1949-10-24 | Improvements in or relating to the production of magnetisable material |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2728349A GB722175A (en) | 1949-10-24 | 1949-10-24 | Improvements in or relating to the production of magnetisable material |
Publications (1)
Publication Number | Publication Date |
---|---|
GB722175A true GB722175A (en) | 1955-01-19 |
Family
ID=10257052
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB2728349A Expired GB722175A (en) | 1949-10-24 | 1949-10-24 | Improvements in or relating to the production of magnetisable material |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB722175A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3036889A (en) * | 1957-04-11 | 1962-05-29 | Frey Friedrich | Process of producing black oxide of iron |
-
1949
- 1949-10-24 GB GB2728349A patent/GB722175A/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3036889A (en) * | 1957-04-11 | 1962-05-29 | Frey Friedrich | Process of producing black oxide of iron |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
MY144555A (en) | Method for manufacturing of insulated soft magnetic metal powder formed body | |
JPS5217696A (en) | Manufacturing process of ferromagnetic grit | |
GB722175A (en) | Improvements in or relating to the production of magnetisable material | |
JPS6033195U (en) | Hot isostatic pressurization device | |
GB874451A (en) | Improvements in or relating to manganese ferrites | |
ES400413A1 (en) | Process for preparing ferromagnetic chromium dioxide | |
GB675195A (en) | Improvements in or relating to magnetic recording member and method of making same | |
JPS5794948A (en) | Photomagnetic recording medium | |
Adachi et al. | Spin Glass State of MnxNi1− xSb: Synthesis in High Pressure and High Temperature Atmospheres | |
GB1417505A (en) | Acicular ferrimagnetic iron oxide containing cobalt and silicon oxide and its production | |
JPS5556019A (en) | Production of ferromagnetic powder | |
JPS5275700A (en) | Production of magnetic iron oxide powder including co | |
GB885118A (en) | Improvements in or relating to the manufacture of silica | |
Ferreira et al. | Study of CoFe2O4/CoFe2 nanostructured powder | |
JPS56153532A (en) | Magnetic recording tape and its manufacture | |
SU589265A1 (en) | Method of heat treatment of iron-cobalt alloys | |
GB1437409A (en) | Methods of making acicular goethite powder | |
GB674960A (en) | Method of forming on iron or an iron alloy a surface easily wettable by mercury | |
JPS5388698A (en) | Production of beta-iron oxyhydroxide powder | |
JPS5711833A (en) | Preparation of thin oxide magnetic film | |
JPS565333A (en) | Preparation of black iron oxide | |
JPS55167139A (en) | Manufacture of oxide magnetic thin film | |
GB899680A (en) | Improvements in or relating to magnetic recording powders | |
JPS5764904A (en) | Manufacture of ferromagnetic metallic powder | |
GB387009A (en) | Improvements in and relating to the heat treatment of magnetic materials |