Abstract:
Ferromagnetic metal particles of substantially iron are prepared by starting from an acicular .alpha.-FeOOH, applying a shape-stabilizing finish to the particle surface, heating at 500.degree.-850.degree. C. and subsequently reducing with gaseous reducing agents at 200.degree.-500.degree. C. to the metal, and starting .alpha.-FeOOH being prepared in the presence of zinc and phosphate ions.
Abstract:
Acicular ferromagnetic metal particles consisting essentially of iron are prepared by a process wherein acicular iron(III) oxide hydroxide provided with a shape-stabilizing surface coating, or iron(III) oxide obtained therefrom by dehydration, is reduced by means of a decomposable organic compound and hydrogen.
Abstract:
A process for stabilizing pyrophoric acicular metal particles consisting essentially of iron, by reaction with oxygen-containing gases in two stages, wherein, in the first stage, up to 1/3 of the passivating layer present in the final state is formed at from 25.degree. to 45.degree. C. and, in a subsequent second stage, the remainder of the passivating layer is formed at from 50.degree. to 70.degree. C.
Abstract:
Multilayer magnetic recording medium which is suitable for high recording densities and the recording of digital data, has very good electromagnetic recording properties and good surface smoothness and can absorb a large amount of lubricant in the lower layer and has at least one upper magnetic recording layer less than 0.5 μm thick and at least one lower layer which contains a magnetically soft pigment.
Abstract:
A magnetic recording medium which consists of at least two layers cast one on top of the other is described, the lower layer containing acicular magnetic pigments having a field strength of 5-40 kA/m and a magnetization of 20-70 nTm3/g and the upper layer containing a high-density metal powder dispersion. After application of the layers, the magnetic recording medium is subjected to a magnetic disorientation treatment while the layers are in the wet state, so that said recording medium has virtually no magnetic and mechanical anisotropy. The magnetic recording medium produced in this manner is particularly suitable for floppy disks having a high storage capacity of substantially more than 100 megabytes.
Abstract:
A method and an arrangement for reducing wear in magnetic storage means having magnetic disks, in particular having flexible media, become effective when predetermined maximum waiting times of the heads on the same track or the same tracks have elapsed. The heads HD are moved away from the waiting tracks in accordance with the predetermined control scheme, may be moved in waiting areas of the magnetic surface, and are moved back to the waiting position.
Abstract:
In magnetic recording media which have at least one magnetizable layer firmly applied to a nonmagnetic base, the magnetizable layer essentially consists of a magnetic material finely dispersed in an organic polymer binder, a dispersant, a lubricant and other conventional additives.
Abstract:
Finely divided, acicular and pore-free .alpha.-Fe.sub.2 O.sub.3 is prepared from iron(III) salts in the presence of one or more organic substances which form complexes with iron(III) ions, in alkaline suspension, at from 80.degree. to 250.degree. C.
Abstract translation:在一种或多种有机物质的存在下,在碱性悬浮液中,在80-250℃下,由铁(III)盐制备细小的针状和无孔的α-Fe 2 O 3,所述有机物与铁(III)离子形成络合物 。
Abstract:
Ferromagnetic chromium dioxide is improved by subjecting chromium dioxide materials prepared by a known method to an additional heat treatment.