Synthesis of γ-alumina nanoparticles by wire-explosion process: Characterisation and formation mechanism
01 Oct 2017-pp 301-306
TL;DR: In this paper, a single-step synthesis of γ-alumina (γ-Al 2 O 3 ), by wire-explosion process (WEP), is described.
Abstract: Single-step synthesis of γ-alumina (γ-Al 2 O 3 ), by wire-explosion process (WEP), is described in this work. Molecular oxygen is used as ambient gas with different levels of pressure to obtain the corresponding oxide nanoparticles (NPs). The energy (E) deposited to the capacitor, used for the explosion is in multiples of the sublimation energy. XRD and TEM techniques are used to characterise the synthesized nanoparticles. The content of γ-Al 2 O 3 increases with increase in E and/or oxygen pressure (P). The average particle size of the nanoparticles reduces with the increase in E and/or decrease in P. The Born-Haber cycle is used to calculate the lattice energy (LE) of the bulk Al 2 O 3 . The dependence of LE and the formation enthalpy of alumina nanoparticles with size are evaluated. A classical homogenous nucleation theory is used to see the effect of saturation ratio and temperature on the activation energy and the nucleation rate of the NPs correlating it with size dependence on E and P used in the WEP.
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01 Jan 2007
TL;DR: Al2O3 nanoparticles as discussed by the authors, a type of butyl nanoparticles, have been used in the development of Al2O 3 nanoparticles. Butyl is a powerful compound that has been shown to have promising properties in the detection of cancer.
Abstract: Al2O3 nanoparticles 被聚乙二醇辛基苯基醚(三重氢核 X-100 ) 准备 /n-butyl 白酒 / 环己烷 / 水 W/O 反向的微乳液。合适的锻烧温度被先锋产品的热分析在 1 150 ° C 决定。Al2O3 nanoparticles 的结构和形态学被 X 光检查衍射，传播电子显微镜学和紫外力的系列描绘。到形态学和 Al2O3 nanoparticles 的尺寸上的表面活化剂的水的鼹鼠比率的影响被学习。随表面活化剂内容的增加，粒子尺寸变得更大。nanoparticles 的凝块成功地被解决。并且在反向的微乳液的 Al2O3 nanoparticles 的形成机制也被讨论。
5 citations
01 Jun 2019
TL;DR: In this paper, the synthesis of MoC 1-x nanoparticles (NPs) with Mo wire as starting material and to carryout explosion in the methane gas medium, which acts as carburizing medium, as well as a coolant, to bring down the local temperature rise to a value lower than the melting point of the material.
Abstract: We propose the synthesis of MoC 1-x nanoparticles (NPs) with Mo wire as starting material and to carryout explosion in the methane gas medium, which acts as carburizing medium, as well as a coolant, to bring down the local temperature rise to a value lower than the melting point of the material. To control the phase and morphology of NPs, two parameters are defined in wire explosion process (WEP): energy ratio, K (ratio of energy supplied to wire and sublimation energy of wire) and pressure, P of ambient gas. XRD, TEM, SEM and XPS were used to characterize the synthesized NPs. Pure Moc 1-x was synthesized for K = 5.8 and P = 170 kPa. Carburization is more for high K/P. For low pressure case, one has to provide more K to get complete carburization. XPS confirms the formation of MoC without any oxidation of Mo vapour. Spherical NPs were obtained with least mean particle size of 20 nm. Particle size decreases with increase in K and/or decrease in P.
Cites background or methods from "Synthesis of γ-alumina nanoparticle..."
...Wire explosion process (WEP) offers single step synthesis method of NPs with least number (two) of precursors [12-17]....
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...In one setup, one can form metal [12], its oxide [15], carbide [16], alloy [17] and other composite NPs by exploding the suitable wire in appropriate ambient....
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References
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TL;DR: Hydrogen Production by Water−Gas Shift Reaction 4056 4.1.
Abstract: 1.0. Introduction 4044 2.0. Biomass Chemistry and Growth Rates 4047 2.1. Lignocellulose and Starch-Based Plants 4047 2.2. Triglyceride-Producing Plants 4049 2.3. Algae 4050 2.4. Terpenes and Rubber-Producing Plants 4052 3.0. Biomass Gasification 4052 3.1. Gasification Chemistry 4052 3.2. Gasification Reactors 4054 3.3. Supercritical Gasification 4054 3.4. Solar Gasification 4055 3.5. Gas Conditioning 4055 4.0. Syn-Gas Utilization 4056 4.1. Hydrogen Production by Water−Gas Shift Reaction 4056
7,067 citations
"Synthesis of γ-alumina nanoparticle..." refers background in this paper
...-Alumina ( -Al2O3) NPs find its application in numerous fields as development of wear resistant materials [1], paint industry, bactericidal agent [2], catalysis [3], degradation of pollutants [4], production of biofuels [5], etc....
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TL;DR: A review on fluid flow and heat transfer characteristics of nanofluids in forced and free convection flows is presented in this article, where the authors identify opportunities for future research.
1,988 citations
"Synthesis of γ-alumina nanoparticle..." refers methods in this paper
...In insulation technology it is used as filler for nanocomposites [6] to get the needed properties of the insulation and as an ingredient in nanofluids [7, 8] to tune the properties of insulating/cooling fluids used in power apparatus....
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TL;DR: In this article, the future of mesoscopic properties of nanocomposite polymers is discussed, and several interesting results to indicate the foreseeable future have been revealed, some of which are described on materials and processing, together with basic concepts and future direction.
Abstract: Polymer nanocomposites are defined as polymers in which small amounts of nanometer size fillers are homogeneously dispersed by only several weight percentages. Addition of just a few weight percent of the nanofillers has profound impact on the physical, chemical, mechanical and electrical properties of polymers. Such change is often favorable for engineering purpose. This nanocomposite technology has emerged from the field of engineering plastics, and potentially expanded its application to structural materials, coatings, and packaging to medical/biomedical products, and electronic and photonic devices. Recently these 'hi-tech' materials with excellent properties have begun to attract research people in the field of dielectrics and electrical insulation. Since new properties are brought about from the interactions of nanofillers with polymer matrices, mesoscopic properties are expected to come out, which would be interesting to both scientists and engineers. Improved characteristics are. expected as dielectrics and electrical insulation. Several interesting results to indicate the foreseeable future have been revealed, some of which are described on materials and processing in the paper together with basic concepts and future direction.
889 citations
"Synthesis of γ-alumina nanoparticle..." refers methods in this paper
...In insulation technology it is used as filler for nanocomposites [6] to get the needed properties of the insulation and as an ingredient in nanofluids [7, 8] to tune the properties of insulating/cooling fluids used in power apparatus....
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TL;DR: In this article, a solid lubricant composite material was made by compression molding PTFE and 40nm alumina particles using a jet milling apparatus and tested against a polished stainless steel counterface on a reciprocating tribometer.
571 citations
"Synthesis of γ-alumina nanoparticle..." refers background in this paper
...-Alumina ( -Al2O3) NPs find its application in numerous fields as development of wear resistant materials [1], paint industry, bactericidal agent [2], catalysis [3], degradation of pollutants [4], production of biofuels [5], etc....
[...]
TL;DR: In this paper, an expression for the size-dependent melting for low-dimensional systems is derived on the basis of an analogy with the liquid-drop model and compared with other theoretical models as well as the available experimental data in the literature.
Abstract: Empirical relations are established between the cohesive energy, surface tension, and melting temperature of different bulk solids. An expression for the size-dependent melting for low-dimensional systems is derived on the basis of an analogy with the liquid-drop model and these empirical relations, and compared with other theoretical models as well as the available experimental data in the literature. The model is then extended to understand (i) the effect of substrate temperature on the size of the deposited cluster and (ii) the superheating of nanoparticles embedded in a matrix. It is argued that the exponential increase in particle size with the increase in deposition temperature can be understood by using the expression for the size-dependent melting of nanoparticles. Superheating is possible when nanoparticles with a lower surface energy are embedded in a matrix with a material of higher surface energy in which case the melting temperature depends on the amount of epitaxy between the nanoparticles and the embedding matrix. The predictions of the model show good agreement with the experimental results. A scaling for the size-dependent melting point suppression is also proposed.
543 citations
"Synthesis of γ-alumina nanoparticle..." refers methods in this paper
...Size dependent lattice energy (SDLE) of the Al2O3 nanoparticle ( ) is predicted using Modified Nanda’s SDCE (Size dependent cohesive energy) model [23, 24] given by Equation 4....
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