Advances in Nanoalumina Ceramic Particle Fabrication Using Sonofragmentation
TL;DR: In this article, the effects of various parameters such as ultrasonic frequency, feed concentration, sonication time, surfactant, and applied ultrasonic power on sonofragmentation were investigated.
Abstract: The present study is focused on fabrication of high-purity submicrometer alumina ceramic particles (predominantly in sub-100 nm range) from micrometer-sized feed (e.g., 70-80 mum) using sonofragmentation. The effects of various parameters such as ultrasonic frequency, feed concentration, sonication time, surfactant, and applied ultrasonic power on sonofragmentation were investigated. Sub-100 nm particle production by sonofragmentation was validated via three metrics, i.e., laser particle size analysis, high-resolution transmission electron microscopy, and turbidimetry. There is a significant change in color and shape of alumina ceramic particles as a result of sonofragmentation. Higher size reduction ratios are obtained at lower frequencies and at higher input power. Submicrometer particle generation increases as concentration of the feed particles increases, indicating that attrition by interparticle collision is a significant mechanism. The shape of the particles changes from angular to spherical as sonofragmentation time increases. Probe-type sonication produces fragmentation effects that are less uniform than those induced by tank-type ultrasonics. Surfactant plays a significant role in preventing agglomeration, especially as finer fragments are produced with prolonged sonication.
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14 Jul 2017
TL;DR: In this article, a simple route to prepare Gd0.7Sr0.3MnO3 nanoparticles by ultrasonication of their bulk powder materials is presented.
Abstract: A simple route to prepare Gd0.7Sr0.3MnO3 nanoparticles by ultrasonication of their bulk powder materials is presented in this article. For comparison, Gd0.7Sr0.3MnO3 nanoparticles are also prepared by ball milling. The prepared samples are characterized by x-ray diffraction (XRD), field emission scanning electron microscope (FESEM), energy dispersive x-ray (EDX), x-ray photoelectron spectroscope (XPS), and superconducting quantum interference device (SQUID) magnetometer. XRD Rietveld analysis is carried out extensively for the determination of crystallographic parameters and the amount of crystalline and amorphous phases. FESEM images demonstrate the formation of nanoparticles with average particle size in the range of 50–100 nm for both ultrasonication and 4 h (h) of ball milling. The bulk materials and nanoparticles synthesized by both ultrasonication and 4 h ball milling exhibit a paramagnetic to spin-glass transition. However, nanoparticles synthesized by 8 h and 12 h ball milling do not reveal any phase transition, rather show an upturn of magnetization at low temperature. The degradation of the magnetic properties in ball milled nanoparticles may be associated with amorphization of the nanoparticles due to ball milling particularly for milling time exceeding 8 h. This investigation demonstrates the potential of ultrasonication as a simple route to prepare high crystalline rare-earth based manganite nanoparticles with improved control compared to the traditional ball milling technique.
17 citations
TL;DR: A simple route to prepare Gd$0.7}$Sr$ 0.3}$MnO$_3$ nanoparticles by ultrasonication of their bulk powder materials is presented in this article.
Abstract: A simple route to prepare Gd$_{0.7}$Sr$_{0.3}$MnO$_3$ nanoparticles by ultrasonication of their bulk powder materials is presented in this article. For comparison, Gd$_{0.7}$Sr$_{0.3}$MnO$_3$ nanoparticles are also prepared by ball milling. The prepared samples are characterized by X-ray diffraction (XRD),field emission scanning electron microscope (FESEM), energy dispersive X-ray (EDX), X-ray photoelectron spectroscope (XPS), and Superconducting Quantum Interference Device (SQUID) magnetometer. XRD Rietveld analysis is carried out extensively for the determination of crystallographic parameters and the amount of crystalline and amorphous phases. FESEM images demonstrate the formation of nanoparticles with average particle size in the range of 50-100 nm for both ultrasonication and 4 hours (h) of ball milling. The bulk materials and nanoparticles synthesized by both ultrasonication and 4 h ball milling exhibit a paramagnetic to spin-glass transition. However, nanoparticles synthesized by 8 h and 12 h ball milling do not reveal any phase transition, rather show an upturn of magnetization at low temperature. The degradation of the magnetic properties in ball milled nanoparticles may be associated with amorphization of the nanoparticles due to ball milling particularly for milling time exceeding 8 h. This investigation demonstrates the potential of ultrasonication as a simple route to prepare high crystalline rare-earth based manganite nanoparticles with improved control compared to the traditional ball milling technique.
16 citations
TL;DR: Data science is utilized in a way that can elucidate structure-property relationships in colloidal chemistry, providing a more efficient way to evaluate the synthesis and processing of materials with high experimental dimensionality.
16 citations
TL;DR: In this article, an approach for a convenient fabrication of titanium nitride (TiN) particulate reinforced commercially pure aluminum (CP Al) composites via ultrasonic cavitation was proposed.
15 citations
TL;DR: In this article, X-ray powder diffraction results showed that face centered cubic cubic CeO2-nanoparticles with crystalline size in nanometer scale were formed by a low temperature chemical precipitation method, where the precursor materials used were Ce(NO3)3.6H2O, NaOH and diethylene glycol as surfactant.
Abstract: Nano-crystalline particles of CeO2 have been synthesized by a low temperature chemical precipitation method. The precursor materials used in this research were Ce(NO3)3.6H2O, NaOH and diethylene glycol as surfactant. X-ray powder diffraction results showed that face centered cubic CeO2 nanoparticles with crystalline size in nanometer scale were formed. Scanning electron microscopy measurement showed that by increasing the calcinations temperature the crystallite size decreases. The particle size of CeO2 was around 20 nm as estimated by X-ray powder diffraction technique and direct high-resolution transmission electron microscopy observation. High-resolution transmission electron microscopy studies showed the size of CeO2 particles increase from 10-90 nm by increasing the ratio of diethylene glycol surfactant. The sharp peaks in Fourier transform infrared spectrum determined the purity of CeO2 nanoparticles and absorbance peak of ultraviolet–visible spectroscopy spectrum showed the small bandgap energy of 3.26 ev.
14 citations
Cites background from "Advances in Nanoalumina Ceramic Par..."
...The exhibited picks correspond to the (111), (200), (220), (311), (222), (400), (331) and (420) of a cubic fluorite structure of CeO 2 is identified using the standard data [17,16]....
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References
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TL;DR: Investigating the effect of sonication on the particle size and structure of a well-crystallized (KGa-1) kaolinite from Georgia showed that particle-size reduction can be controlled through different variables such as power of ultrasonic processor, amount of sample, and time of treatment.
221 citations
TL;DR: In this article, pressureless sintered alumina compacts with a submicrometer microstructure exhibit a hardness that approaches or even exceeds the level of advanced hot-pressed composites of Al{sub 2 O{sub 3} + 35 vol% TiC, whereas the strength of both ceramics is approximately the same.
Abstract: Pressureless sintered alumina compacts with a submicrometer microstructure exhibit a hardness that approaches or even exceeds the level of advanced hot-pressed composites of Al{sub 2}O{sub 3} + 35 vol% TiC, whereas the strength of both ceramics is approximately the same. The combination of reduced dislocation mobility (due to the small grain size), high density, and density homogeneity are the prerequisites for the surprisingly high hardness. Quasi-conventional powder processing is used to produce these outstanding alumina bodies.
200 citations
TL;DR: In this article, a review of the fracture properties of nanocomposites is presented, emphasizing the newly developed concept of material design for ceramics and several mechanisms proposed previously to explain these characteristics were reviewed.
177 citations
TL;DR: In this paper, a theory for ultrasonic fragmentation of agglomerate particles suspended in liquids is presented, and an expression for the fragmentation rate as a function of ultra-osnic power and agglerate size is derived.
134 citations
"Advances in Nanoalumina Ceramic Par..." refers background in this paper
...Ultrasonic fragmentation of alumina particles [8], [9] to produce a fine fraction of crystalline materials to produce particles in the 10-μm-size range, and of kaolinite [10] in the 1–2-μm-size range are examples of studies reported in literature....
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TL;DR: In this paper, the structure of as-synthesized samples (ZrO{sub 2}{center_dot}nH{sub2}O) and the formation mechanism of ZrO-sub 2} nanopowders are also discussed.
95 citations
"Advances in Nanoalumina Ceramic Par..." refers background in this paper
...nano-ZrO2 powders [14] are produced via sonochemical methods, which are simple and energy efficient....
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...Fragmentation by conventional attritional means such as grinding or milling is reported widely in literature, but contamination from the milling material, as well as energy efficiency, are definite drawbacks [2]–[6]; comminution by high-intensity ultrasound has also been studied [7]–[14], but to a lesser extent....
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