PROCESS OF MANUFACTURE OF FERROMAGNETIC FLUID Russian patent published in 1994 - IPC

FIELD: electrical engineering. SUBSTANCE: process of production of high-temperature ferromagnetic fluid possessing thermal oxidizing resistance uses alcaren which is nontoxic, high-vacuum and high-temperature oil with perfect lubricating properties as liquid medium. process lies in precipitation of highly dispersing magnetite in alkali medium from aqueous solution of salts of iron, in washing of precipitate with distilled water and in peptization in solution of oleic acid in alcaren at 388-393 K under vacuum. Produced high-temperature ferromagnetic fluid has density 1,21·10³ kg·m^-3, viscosity 2,3·10^-1 Pa·c, magnetic permeability 1.3; magnetization saturation 22,5 kА·m^-1. Ferromagnetic fluid is stable in gravitation field of 6000 g, in magnetic field up to 1.0 Tm and can be used at temperature from 233 K up to 453 K. EFFECT: facilitated manufacturing process, increased working properties.