Fabrication of spherical particles with mixed amorphous/crystalline nanostructured cores and insulating oxide shells

Abstract

By spark-eroding Fe75Si15B10 in water/ethanol mixtures, spherical particles with nanostructured cores consisting of mixed amorphous and crystalline phases were produced. The relative volume fractions of the amorphous and crystalline phases were dependent on the water/ethanol ratio. In the same process, continuous oxide layers were formed on the particle surfaces. The basic mechanisms responsible for the formation of the surface oxide layers and the core nanostructures were modeled. At frequencies ranging from 1 to 100 MHz, the combination of the core nanostructures and the insulating oxide shells yielded exceptionally low-loss magnetic behavior.

Investigation of the synthesis of nanoparticles by pulsed electrical erosion in the conditions of overvoltage of the discharge gap

“…Further studies aimed at studying the method of electrospark erosion confirmed the possibility of obtaining nanoparticles of various conductive materials, including complex composition [8,9]. Investigations of the influence of dielectric liquid media used in the synthesis of nanoparticles [10], including cryogenic liquids [11], have been carried out.…”

Features of the Formation of Multi-Channel Pulse Currents and Fast-Migrating Electric Sparks in the Layer of Current-Conducting Granules of Electric-Discharge Installations

“…It was also substantiated that electric-spark machining can be a promising method for dispersion of the refractory, superhard and ductile metals, alloys and composites to obtain micro-and nanoparticles with unique operational properties [3,6,8]. This method allows to obtain powder micro-and nanostructured magnetic materials with shape memory [9], dispersion-strengthened refractory alloys [10,11], surface active hydroxides, oxides, carbides, and nitrides [8][9][10][11]. The possibility of processing industrial metal waste into highly dispersed powders with a highly developed active surface increased the relevance of this line of research.…”

Analytical Nonlinear-Probabilistic Model of the Equivalent Electrical Resistance of a Layer of Metal Granules

“…Іскро-та плазмоерозійна обробка шарів металевих гранул (ШМГ) в робочих рідинах є основою чотирьох основних груп технологічних процесів. До першої відноситься виробництво мікродисперсних порошків металів і сплавів із спеціальними властивостями: тугоплавких і жароміцних [1], з магнітною [2] і температурною [3] пам'яттю форми, з аморфною [4] та аморфно-кристалічною структурою [5], з гігантським магніторезистивним ефектом [6], магнітом'яких [7], воденьсорбуючих, надтвердих [8], корозійно стійких [9] та ін. [10][11][12].…”