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MATERIALS BASED ON MAGNETIC NANOPARTICLES OF MAGNETITE-TYPE, COVERED WITH A DOUBLE INORGANIC LAYER AND PROCESS FOR PREPARING THE SAME
MATERIALS BASED ON MAGNETIC NANOPARTICLES OF MAGNETITE-TYPE, COVERED WITH A DOUBLE INORGANIC LAYER AND PROCESS FOR PREPARING THE SAME
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机译:基于磁铁矿型磁性纳米粒子的材料,包覆有双重无机层,并制备相同的材料
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摘要
The invention relates to a process for preparing magnetic nanoparticles used as pigments for manufacturing security paper. According to the invention, the process comprises the magnetite-forming reaction, after which the magnetic nanoparticles are covered with a layer of barium sulphate, resulting in nanoparticles of the type FeO/BaSOwhich are magnetically dispersed from the reaction mass, are successively washed with ethanol and water and are subjected to reaction with tetraethyl orthosilicate in a ratio of 1:2 in a mixture of ethanol, water and ammonia, at room temperature, for 3 h, while continuously stirring, the formed particles being magnetically separated, washed with water and ethanol and dried, resulting in magnetic nanoparticles of magnetite type covered with a doube inorganic layer of barium sulphate and silicon dioxide.
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