The nano aluminium particles were produced in different ambience by the wire explosion process. The influence of pressure in the exploding wire chamber on the size of the particles was analyzed. Certain physico-chemical diagnostic studies, viz., wide angle X-ray diffraction (WAXD), thermo-gravimetric differential thermal analysis (TG-DTA) studies were carried out to characterize the produced nano aluminium powder. The compositions of the material were characterized through the energy dispersive analysis by X-ray (EDAX) results. The size of the particles was measured using transmission electron microscope (TEM) studies and particle size distribution analyses were carried out by adopting log-normal distribution. The mechanism of formation of nano powder by wire explosion technique was explained in detail. © 2006 Elsevier Inc. All rights reserved.

Ramanujam Sarathi

Department of Electrical Engineering

Satyanarayanan R. Chakravarthy

Department of Aerospace Engineering

Aluminum

Characterization

Energy dispersive spectroscopy

Particle size analysis

Plasmas

Powder metals

Thermogravimetric analysis

Transmission electron microscopy

X ray diffraction

ALUMINIUM PARTICLES

LOG NORMAL DISTRIBUTION

WIRE CHAMBERS

WIRE EXPLOSION

Nanostructured materials

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

Materials Characterization

Pulsed wire discharge was used to prepare nanoparticles of molybdenum and its carbides from Mo wires in a gas mixture of argon and kerosene at pressures of 100, 50, and 25 kPa. The different pressures affected the carburization process and particle formation. The most effective pressure was 25 kPa, where the volume fraction of MoC was identified by Rietveld refinement of X-ray diffraction data to be 98.4%. The particle size distribution was also obtained from transmission electron microscopy measurements, and the smallest geometric mean diameter was determined tobe 24.3 nm for the sample prepared at 25 kPa. © 2019 The American Ceramic Society

Journal of the American Ceramic Society

Synthesis of molybdenum carbide nanoparticles using pulsed wire discharge in mixed atmosphere of kerosene and argon

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

Aluminum-water reaction based ramjet propulsion system shows higher theoretical performance when compared to the conventional solid propellant based propulsion system for high-speed underwater applications. In the present study, theoretical performance calculations and also the primary combustion characteristics of the water ramjet have been studied using window bomb test facility. The aluminized solid fuel-rich propellant compositions contain 40-50% of aluminum with the particle sizes of 110 nm, 250 nm and 18 µm which also comprises of 34.5-46% of Ammonium Perchlorate (AP) in a total of 15 formulations in the 0.2–3.1 MPa pressure range are considered in this study. Paraffin wax and HTPB based binders are used for the preparation of nano and micro aluminized propellants respectively. In comparison with Mg, Al-based water ramjet shows higher theoretical specific impulse for Rwf greater than 0.5. The stoichiometry of Al-based water ramjet occurs at Rwf of 0.5 and it shifts towards a slightly higher value of Rwf when the Al content increases to 50%. Combustion of 50% aluminized propellant compositions causes more than 40-50% of initial mass as residue which mainly contains unreacted aluminum and other condensed phase combustion products. Nano aluminized propellant compositions show 2-5 times the higher burning rate than the micro aluminized counterparts in the CO2 atmosphere. These propellants exhibit a wide range of pressure indices (n) from 0.23 to 0.56. © 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

2018 Joint Propulsion Conference

Effect of aluminum particle size on primary combustion and performance of water ramjet

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.

Fulltext

IOP Conference Series: Materials Science and Engineering

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

IEEJ Transactions on Fundamentals and Materials

Particle Size Distribution of Copper Nanosized Powders Prepared by Pulsed Wire Discharge

Journal of Korean Powder Metallurgy Institute

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

Scripta Materialia

Ultra-fine powder by wire explosion method

IEEE Transactions on Plasma Science

The current density and the specific energy input in fast electrical explosion

Pulsed wire discharge for nanosize powder synthesis

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

Journal	Materials Characterization
ISSN	10445803
Open Access	No