摘要:
Acicular ferromagnetic chromium dioxide is stabilized by treatment with an alkali metal hydroxide in an aqueous alkaline suspension at elevated temperatures.
摘要:
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.
摘要:
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.
摘要翻译: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 。
摘要:
The preparation of acicular ferrimagnetic iron oxides which contain cobalt and phosphate ions and, if desired, further additives, and their use for manufacturing magnetic recording media.
摘要:
A process for the preparation of cobalt-containing isotropic magnetic iron oxides which are based on gamma-iron(III) oxide, contain from 2 to 7% by weight of cobalt(II) ions and less than 2% by weight of Fe(II) ions, the percentages in each case being based on the iron oxide, and have a particle length of from 0.08 to 0.30 .mu.m, a length/width ratio of from 1.5 to 3.5:1 and a specific remanent magnetization after saturation of not less than 60 nTm.sup.3 /g.
摘要:
Acicular .alpha.-Fe.sub.2 O.sub.3 is prepared from iron(III) salts by heating an alkaline aqueous suspension of iron(III) hydroxide in the presence of one or more organic substances which form complexes with iron(III) ions to a temperature of 100.degree. C. or less.
摘要翻译:通过在一种或多种与铁(III)离子形成络合物的有机物质的存在下加热氢氧化铁(III)的碱性水性悬浮液至100℃,由铁(III)盐制备针状α-Fe 2 O 3。 或更少。
摘要:
Acicular, magnetic iron oxide consisting of a core of gamma-iron(III) oxide and a ferrite shell containing a total of from 0.4 to 12% by weight of cobalt(II) ions and from 0.1 to 15% by weight of iron(II) ions, the percentages being based on the total amount of magnetic material, is prepared by a process in which an iron(II) hydroxide precipitate is applied to the gamma-iron(III) oxide core in a first stage and an iron-(II)/cobalt hydroxide precipitate is applied to the said core in a second stage, and the core is then converted to the ferrite shell by oxidation.
摘要:
Acicular, ferromagnetic metal particles which essentially consist of iron and have a nickel content of not more than 0.4% by weight and high values for coercive force and magnetization, and a process for the preparation of these particles. The particles further include zinc, phosphorus in the form of phosphate ions, and silicon in the form of SiO.sub.2.
摘要:
A chromium dioxide material consisting of acicular, ferromagnetic chromium dioxide particles having a nonmagnetic, hydrogen-containing protective surface layer, which material has improved stability to chemical decomposition, a process for its preparation and magnetic recording media containing this chromium dioxide and having good long-term stability of the residual magnetization under conditions of high humidity and temperature are described.
摘要:
Highly viscous magnetic fluids essentially consist of superparamagnetic solid particles coated with a surfactant and colloidally dispersed in a carrier liquid.