In the present study, nano aluminium particles were produced by wire explosion process (WEP) in nitrogen, argon and helium atmospheres. Thus produced nano particles were characterized through certain physico-chemical diagnostic studies using wide angle X-ray diffraction (WAXD) and by energy dispersive analysis by X-rays (EDAX). The size and shape of the powder were analysed by using transmission electron microscopic (TEM) studies. The particle size distribution studies were performed by adopting log-normal probability distribution. The relationship between size of the particle generated in the explosion process and the type of inert gas/pressure was analysed. The mechanisms of nano particle formation, the factors which can aid the process of formation of nano particle in the wire explosion process were analysed. It is realized that energy deposited to the conductor and duration of current flow have major impact on particles produced by this process. © Indian Academy of Sciences.

Ramanujam Sarathi

Department of Electrical Engineering

Satyanarayanan R. Chakravarthy

Department of Aerospace Engineering

Alumina

Energy dispersive spectroscopy

Inert gases

Pressure effects

Transmission electron microscopy

Log-normal distribution

NANO ALUMINIUM POWDER

WIDE ANGLE X-RAY DIFFRACTION (WAXD)

WIRE EXPLOSION PROCESS (WEP)

Nanoparticles

Fulltext

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Bulletin of Materials Science

Micro-electrical discharge machining (µ-EDM) as an advanced mechanical micro-machining method has been widely used in the generation of micro-features by removing debris through melting and evaporation phenomena, and during this time some amount of debris is dispersed in the dielectric medium. These debris are treated as unwanted materials and later will be disposed of from the system. But, after critical evaluation of the debris through transmission electron microscope (TEM), it is found that the debris are agglomerated and in the size range of 40–600 nm (mean size: 242 nm). This makes curious to search for any alternatives to overcome the agglomeration to result into ultrafine particles in the range of nanometres. In the present article, an attempt has been made to incorporate ultrasonication during machining process and also resorted to use stabilizers. As per chemistry aspect of metallic aluminium particles, Poly Ethylene Glycol (PEG), Bael Gum (BG) and ACacia Gum (ACG) stabilizers are used along with deionized (DI) water and studied their effect individually on the interaction between the nucleated nanoparticles. The characterization results reveal that using PEG, BG and ACG, the debris of aluminium generated are in the size range of 45–500 nm (mean size: 196 nm), 25–70 nm (mean size: 45 nm) and 3–30 nm (mean size: 10 nm), respectively. ACG stabilizer was found to be strongly reduce the agglomeration resulting in excellent stable dispersion of the colloidal aluminium nanoparticles. The nature of colloidal samples was studied by ultraviolet–visible (UV–vis) spectroscopy after 2 weeks of their generation. Furthermore, thermal conductivity and viscosity properties are ascertained, and the heat transfer effect has also been studied experimentally using a developed thermal management system. The obtained results are presented in the article. © 2018, © 2018 Taylor & Francis Group, LLC.

Machining Science and Technology

Role of stabilizers on agglomeration of debris during micro-electrical discharge machining

Nanoaluminum particles were generated by a wire explosion process (WEP) in helium, argon, and nitrogen ambiences, by depositing energy equal to the vaporization energy of the conductor material volume. The size and shape of the generated nanoaluminum particles were analyzed using a transmission electron microscope (TEM). X-ray diffraction (XRD) analysis was carried out to characterize the phase in nanoaluminum (Al) particles. Particle size distribution of the produced nano-Al particles follows log-normal distribution and the nanoparticles produced in helium were of smaller size compared to those produced in argon or nitrogen ambience. Hydrogen gas was generated on reacting aluminum nanoparticles with aqueous NaOH solution. It was observed that most of the oxides formed on reaction of Al and aqueous NaOH solution were bayerite at room temperature and boehmite at higher temperature. The formation of bayerite and boehmite was characterized using XRD and TEM studies. The reactions were also carried out at higher temperature to understand the hydrogen generation rate. Molarity of NaOH has a high influence on the rate of hydrogen generation. The rate constant of the reaction was calculated adopting the first order rate law for predicting the amount of hydrogen generation. Nickel (Ni) nanoparticles synthesized by WEP and copper sulfate (CuSO4) were used as catalysts and added to the reaction mixture of Al and aqueous NaOH solution to control the hydrogen generation rate. It was observed that the reaction rate of Al with NaOH medium has increased with the addition of CuSO4 and Ni nanoparticles due to the microgalvanic effect, thereby enhancing the hydrogen generation rate. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley &amp; Sons, Inc. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

IEEJ Transactions on Electrical and Electronic Engineering

Enhancement of hydrogen generation using nanoaluminum particles produced by a wire explosion process

Combustion of sandwiches made of alternating laminae of ammonium perchlorate (AP) and a matrix of hydrocarbon binder mixed with fine AP and nano-aluminium particles is considered in the 1–12 MPa pressure range. Companion non-aluminized sandwiches are studied for comparison. The nano-Al particles are produced from the electrical wire explosion process in the size range ∼45 nm, and added to the matrix containing either 5 or 45 µm AP particles. Three categories of middle lamina thicknesses—thin (100–170 µm), intermediate (200–280 µm), and thick (370–480 µm)—are examined in all the sandwiches. High-speed high-magnification imaging of the combustion is performed, and surface profiles and features of quenched sandwiches are investigated, besides burning rate measurements. The sandwich burning rates are compared with those of the corresponding matrices and AP laminae burning alone as well. The results imply the close location of lamina leading edge flames (L-LEFs) over the lamina interface edges, leaving the outer AP laminae inclined steeply relative to the matrix middle lamina, in the nano-aluminized cases relative to the non-aluminized versions. This observation suggests that the L-LEFs control the burning rates of the sandwiches even in the case of the fast burning matrix that contains nano-Al. The non-aluminized sandwiches containing the 5 µm AP show higher burning rates than their 45 µm AP counterparts because of the enhanced heat feedback available to the matrix burning surface from the extended fuel-rich branches of adjacent L-LEFs in the former case. Therefore, the enhancement in burning rate is minimal with the inclusion of nano-Al in sandwiches with smaller fine AP size, whereas the nano-aluminized sandwiches containing larger fine AP particles exhibit such enhancement. These effects affirm previous results on propellants with smaller fine and coarse AP sizes, where the burning rate is not enhanced by nano-Al. © 2017 The Combustion Institute

Combustion and Flame

Combustion mechanism of composite solid propellant sandwiches containing nano-aluminium

Nanoparticles present a practical way of retaining the results of the property at the atomic or molecular level. Due to the recent use of nanoparticles in scientific, industrial and medical applications, synthesis of nanoparticles and their characterization have become considerably important. Currently, aluminium nanoparticles have attracted significant research attention because of their reasonable cost, unique properties and interdisciplinary emerging applications. The present paper reports the synthesis of aluminium nanoparticles in the mixture of Deionized water (DI water) and Polyethylene Glycol (PEG) using a developed micro-Electrical Discharge Machining (μ-EDM) method. PEG was used as a stabilizer to prevent nanoparticles from agglomeration produced during the μ -EDM process. The synthesized aluminium nanoparticles were examined by Transmission Electron Microscopy (TEM), Energy Dispersive Analysis by X-rays (EDAX) and Selected Area Electron Diffraction (SAED) pattern to determine their size, shape, chemical nature and crystal structure. The average size of the polyhedral aluminium nanoparticles is found to be 196 nm. © Published under licence by IOP Publishing Ltd.

IOP Conference Series: Materials Science and Engineering

Synthesis of Aluminium Nanoparticles in A Water/Polyethylene Glycol Mixed Solvent using μ-EDM

Nano-aluminium particles are produced using the electric wire explosion process in an inert atmosphere at our institute. This paper reports the characterization of nanoaluminium particles in combination with other solid propellant ingredients for their thermal and combustion behaviour. High-heating-rate hot-stage microscopic experiments are performed with different mixtures of propellant ingredients. The effects of addition of nano-aluminium versus micron-sized aluminium in the middle lamina of sandwiches are analyzed for burning rates and by means of scanning electron microscope and transmission electron microscope micrographs of quench-collected aluminium agglomerates. Nano-aluminized sandwiches with thinner middle lamina show slightly higher burning rates than micron-sized aluminized ones. The quenched surface of nano-aluminized sandwiches shows relatively smaller aluminium agglomerates than with micron-sized aluminium. The resultant particle sizes of nano-aluminium agglomerates is in the range of 1-5 μm, which indicates a higher rate of agglomeration than with micro-aluminium, but these sizes are small relative to the agglomerates of the latter. This is also confirmed by quench-collected agglomerates of nano-aluminium emerging from the burning surface of a composite propellant. © 2010 Springer Science+Business Media, Inc.

Combustion, Explosion and Shock Waves

Accumulation of nano-aluminium during combustion of composite solid propellant mixtures

Burning of Nano-Aluminized Composite Rocket Propellants

Journal of Physics D: Applied Physics

The nucleation mechanism of wire explosion

Propellants, Explosives, Pyrotechnics

Productions of Ultra-Fine Powders and Their Use in High Energetic Compositions

Journal of Korean Powder Metallurgy Institute

Synthesis and Compaction of Al-based Nanopowders by Pulsed Discharge Method

IEEE Transactions on Plasma Science

The relationship between exploding wire expansion rates and wire material properties near the boiling temperature

Generation and characterization of nano aluminium powder obtained through wire explosion process

Journal	Bulletin of Materials Science
ISSN	02504707
Open Access	No