scispace - formally typeset
Search or ask a question
Journal ArticleDOI

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.
Citations
More filters
Journal ArticleDOI
TL;DR: In this article, the potential use of halloysite nanotubes (HNT)/Poly(Styrene-co-Methylmethacrylate) (PS-Co-PMMA) nanocomposites as coatings for the protection of soda-lime glass was investigated.

9 citations

Journal ArticleDOI
TL;DR: In this article, the physical properties exhibited the polyvinyl alcohol (PVA) fabricated as a nanofiber composite with embedded strontium hexaferrite nanoparticles (SrM-NPs).

8 citations

Journal ArticleDOI
01 Jun 2014
TL;DR: In this article, the effect of frequency on filler dispersion in the polymer matrix was studied by SEM analysis and functional property enhancement of the composite material was found to be better at low filler loadings as compared with neat polymer and also with composites prepared without ultrasound.
Abstract: Polymer nanocomposites are advanced nanomaterials which exhibit dramatic improvements in various mechanical, thermal and barrier properties as compared with the neat polymer. Polystyrene/ alumina nanocomposites were prepared by an ultrasound-assisted solution casting method at filler loadings ranging from 0.2 to 2% and also at different ultrasonic frequencies, viz. 58 kHz, 192/58 kHz, 430 kHz, 470 kHz and 1 MHz. The composites were subjected to mechanical property tests (tensile and impact tests) and cavitation erosion tests to study the enhancement in functional properties. Filler dispersion in the polymer matrix was observed by SEM analysis. The effect of frequency on filler dispersion in the matrix was studied by SEM analysis and functional property enhancement of the composite material. The composites prepared at dual (high/ low) frequency (192/58 kHz) were found to show better property enhancement at low filler loadings as compared with neat polymer and also with composites prepared without ultrasound, thus reinforcing the finding that ultrasound-assisted synthesis is a promising method for the synthesis of nanocomposites.

7 citations


Cites background from "Advances in Nanoalumina Ceramic Par..."

  • ...1994), and nanoparticle fabrication by sono-fragmentation (Gopi and Nagarajan 2008)....

    [...]

  • ...Ultrasound is used in a variety of applications such as surface cleaning, emulsification, degassing, crystallisation, extraction, for accelerating and performing chemical reactions (Contamine et al. 1994), and nanoparticle fabrication by sono-fragmentation (Gopi and Nagarajan 2008)....

    [...]

Journal ArticleDOI
TL;DR: The use of multidimensional population balance equations in predicting ultrasound assisted sonocrystalization processes is curbed due to the unavailability of physically motivated macroscopic math.
Abstract: The use of multidimensional population balance equations in predicting ultrasound assisted sonocrystalization processes are curbed due to the unavailability of physically motivated macroscopic math...

5 citations

Book ChapterDOI
01 Jan 2016
TL;DR: In this paper, an acoustic cavitation was used to produce very bright mechanoluminescence (ML) from the fracture of piezoelectric crystals, which has been studied for over 400 years, but much is still unknown about it because the emission is inherently weak.
Abstract: Mechanoluminescence (ML): light produced by any mechanical action on a solid. This is a phenomenon that has been studied for over 400 years, but much is still unknown about it because the emission is inherently weak. To advance our understanding of the ML event, ML with greater photon emission is needed. To this end acoustic cavitation has been used to produce very bright ML from the fracture of piezoelectric crystals. The intense shock wave launched from collapsing bubbles during the sonication of slurries allows for the study of chemical and physical events that occur when a solid is stressed or fractured. Sonicating slurries of mechanoluminescent crystals (such as sucrose, sodium chloride, resorcinol, m-aminophenol, or coumarin) in long chain liquid alkanes produce very bright ML, up to and exceeding 1000 times greater intensity than manual grinding. The large increase in intensity has revealed not only emission from bulk gas such as N2 or He but also C2, CH, CO, CO+, CO2+, H, and He+, many of which have not been reported in previous ML studies. In addition, the emission products show that gas phase reactions are occurring within the plasma generated from the ML discharge. The intense ML induced by acoustic cavitation allowed the plasma to be characterized in terms of heavy atom temperature of ~400 K, electron density of ~1014 cm−1, and electron energy of ~3.5 eV. These conditions are very similar to other highly reactive microdischarges.

3 citations

References
More filters
Journal ArticleDOI
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

Journal ArticleDOI
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

Journal ArticleDOI
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

Journal ArticleDOI
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....

    [...]

Journal ArticleDOI
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....

    [...]

  • ...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....

    [...]