Sonochemical Synthesis and Characterization of Manganese Ferrite Nanoparticles

Abstract

This paper reports sonochemical synthesis and characterization of Mn–ferrite nanoparticles using acetates precursors. Mn–ferrite synthesis requires external calcination of oxide precursors formed by sonication. pH does not play a dominant role in the synthesis. Collisions between metal oxide particles induced by shock waves generated by transient cavitation are unable to cross the activation energy barrier for the formation of ferrite. The calcination temperature is a significant parameter that influences the magnetic properties of ferrites. The size, coercivity, and saturation magnetization of ferrite particles increases with the calcination temperature. Ferrites formed at calcination temperatures of 650, 750, and 850 °C show ferromagnetic behavior with easy axis magnetization. Calcination at 950 °C leads to the formation of rods with grain growth that introduces large shape anisotropy. The magnetization curve for rods does not reach saturation, indicating paramagnetic behavior. The cause leading to this effect is nonalignment of the easy axis of magnetization with the direction of the applied magnetic field, resulting in hard axis magnetization.

Recrystallization of phenacetin and sulfathiazole using the sonocrystallization process

“…In In this study, with applying power ultrasound, the mean particle size of phenacetin and sulfathiazole can be efficiently controlled to about 10 μm and the crystal habit could be modified to a regular shape. According to the study of Reddy et al [16] and Goswami [27], the effect of cavitation bubble dynamics is crucial on the particle growth and particle morphology. During sonocrystallization, the size of initially produced crystals is quite small in nanometer scale.…”

Intensification of ultrasound-assisted process for the preparation of spindle-shape sodium zinc molybdate nanoparticles

“…The reaction (ii) and (iii) reports the recombination of radicals so formed to form H 2 and H 2 O 2 . Further, in reaction (iv) the formed H Å and OH Å radicals react with sodium molybdate and zinc oxide to get the required product [25][26][27][28]. Ultrasound plays an important role in producing physical and chemical effects in the reaction medium.…”

“…The ultrasound wave passes through the medium in the form of alternate compression and rarefaction cycles, generating oscillatory motion of fluid elements, which creates intense turbulence and micro-mixing in the reaction medium. The physical and chemical effects generated by cavitation bubbles are well known [25][26][27][28]. The velocity of the bubble wall during compression or collapse phase may reach or exceed the sonic velocity in the liquid medium during high amplitude transient radial motion.…”

Spark plasma sintering and microwave electromagnetic properties of MnFe O4 ceramics

“…[8]. Many synthesis methods have been used for the preparation of MnFe 2 O 4 nanocrystals, such as sonochemical technique [9], microwave-assisted ball milling [8], hydrothermal route [10], solvothermal [11], ultrasonic [12], sol-gel [13], sol-gel auto combustion [14], co-precipitation [15] and thermal decomposition [16] method. For many applications in electronic devices, a solid, high density material is needed, instead of a powder.…”