METHOD OF OBTAINING MAGHEMITE NANOPARTICLES AND SUPERPARAMAGNETIC POWDER COMPOSITION Russian patent published in 2014 - IPC C01G49/06 B82B3/00 B82Y99/00 H01F1/01 

FIELD: chemistry.

SUBSTANCE: invention can be used in inorganic chemistry. In order to obtain maghemite nanoparticles a water iron (III) chloride solution is prepared, an alkali is added to it to pH 6.5-8, heated to 60-70°C, washed until coloration of washing water starts. An agent, regulating the growth of iron oxide nanoparticles is added into the obtained suspension, and the alkali is re-introduced until the solution with pH 8-12 is obtained. After that, the suspension is heated to 130-190°C and exposed at the said temperature for 103 hours. Then, the obtained suspension is centrifuged, washed and dried until it starts crumbling. The iron (III) chloride solution is preliminarily filtered, centrifuged, and 25-38% hydrochloric acid is added to it until the solution pH value is 0.1-1.0. As the agent, regulating the growth of nanoparticles, phosphonic (oxyethylidenediphosphonic, nitrilotrimethylphosphonic, phosphonoacetic), hydroxypolycarboxylic (citric, tartaric), polycaboxylic (glutaric, adipinic, fumaric, maleinic) acids, or their amino acids (aminoacetic, 2-aminipropanic), or their mixtures are taken in an amount of 3·10^-3-1.2·10^-1 mole per a mole of iron. The supermagnetic powder composition contains maghemite and a protective coating, including the adsorbed agent, regulating the growth of nanoparticles.

EFFECT: invention makes it possible to simplify obtaining the maghemite nanoparticles, increase the chemical stability of the obtained supermagnetic nanoparticles of a spherical shape with the size less than 10 nm.

4 cl, 3 dwg, 10 ex