METHOD FOR PRODUCING NANOPARTICLES FOR FERROFLUIDS BY ELECTRON-BEAM EVAPORATION AND CONDENSATION IN VACUUM, A FERROFLUID PRODUCING METHOD AND A FERROFLUID PRODUCED ACCORDING TO SAID METHOD

摘要

The invention relates to producing ferrofluids and to novel material synthesis. The inventive method for producing nanoparticles for ferrofluids by electron-beam evaporation and condensation in vacuum, consists in evaporating an initial solid material and in fixing nanoparticles to a cooled substrate by means of a solidifiable carrier during vapour condensation, wherein a solid inorganic material, which is selected from a group containing metals, alloys or oxides thereof, is used as an initial material and a solid liquid-soluble material is used as a magnetic carrier material for fixing nanoparticles. The method also consists in simultaneously evaporating the initial material and the carrier composition, in which the carrier concentration ranges from 99 to 77%, by electron-beam heating. The vapour is deposited on the substrate, the temperature of which is set and maintained at a specified value, which is lower than the melting point of the carrier material, and the condensate of the magnetic material nanoparticles, which have the specified size and are fixed in the solid carrier, is produced. The particle size is adjusted by setting the specified temperature of the substrate during vapour deposition. A solid inorganic material, which is selected from a group containing salts of alkali and alkali-earth metals and mixtures thereof is used in the form of a magnetic carrier material used for fixing nanoparticles. The nanoparticles are extracted from the above-mentioned condensate by diluting it in at least one type of liquid and by stabilising by a surface-active agent.