Magnetic Nanopowders:  Ultrasound-Assisted Electrochemical Preparation and Properties

Abstract

The development of cost-effective nanopowder production methods has been a major obstacle to the development and industrial utilization of nanostructured materials. This paper describes a new cost-effective production technology for these materials which combines both pulsed electrochemistry and pulsed ultrasound. This technique has been applied to the synthesis of pure and binary and ternary alloyed nanopowders containing iron, cobalt, and nickel. The resulting nanopowders have been characterized by transmission electron microscopy, X-ray fluorescence, transmission high-energy electron diffraction, X-ray diffraction, and Mössbauer spectroscopy. The results indicate that this new production method is ideal for the preparation of high performance nanocomposite powders and related high-density nanocomposite materials.

Organometallic Synthesis of Size‐Controlled Polycrystalline Ruthenium Nanoparticles in the Presence of Alcohols

“…[12] Other synthetic methods involve radiolytic, [31,32] electrochemical, [33,34] or ultrasound-assisted electrochemical synthesis. [35] The particles are usually stabilized by the addition of a surfactant, polymer, or ligand to the reaction mixture in order to prevent undesired agglomeration and metal precipitation. The drawback of these methods may be the presence of surface contaminants resulting from the reaction conditions, such as water, salts, organic residues, or even an oxide shell, which can alter the physical properties of the particles or limit access to their surface.…”

Preparation of nano-Cu2O/TiO2 photocatalyst from waste printed circuit boards by electrokinetic process

“…where C o is the initial concentration of MB and C t the MB concentration after illumination time t. There have been several reports about the synthesis of metal nanoparticles by direct electroreduction of bulk metal ions in aqueous electrolytes [21][22][23]. The main difficulty is that electroreduction of metal ions involves a competition of two completely opposite cathode surface processes: the formation of metal nanoparticles and the metal electrodeposition on cathode [24].…”

Sonoelectrochemical (20 kHz) production of Co65Fe35 alloy nanoparticles from Aotani solutions

“…The primary role of ultrasound in these processes is to induce cavitation in the electrolytic solution which will then ablate the metallic nuclei formed during the short electrodeposition period from the cathodic surface [14,16,[21][22][23][24][25][26]. I is the applied current (mA); t ON is the applied current pulse time (s); t US is the applied ultrasonic pulse time (s); t p is the rest time (s); v is the varying process parameter; m f is the faradic yield (mg); m r is the actual yield (mg); g is the cathode efficiency (%)…”

“…magnetic recording, catalysis, and medicine [10][11][12][13][14][15][16]. There are a range of methods of producing metallic nano-sized materials including thermal decomposition [17,18], physical and thermal evaporation [6,17], laser ablation [19], laser-assisted catalytic growth (LCG) [11,12], vapor-liquid-solid growth (VLS) [11], chemical oxidation [12] and sol-gel methods [13].…”

“…This 'sonotrode' or 'sonoelectrode' was subjected to short applied current pulses which were each followed by ultrasonic pulses. They showed that, during cavitation, a jet of liquid penetrates inside the cavitation bubble perpendicular to the 'sonoelectrode' surface [16] and the resulting impact was responsible for dislodging any nanopowder material which had been electrochemically deposited on the surface. This new sonoelectrochemical method has since been employed to produce several pure metallic, alloy [14,[20][21][22] and semiconductor nanoparticles [23][24][25][26].…”