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Thermal characterization and kinetic analysis of nano‐ and micro‐Al/NiO thermites: Combined experimental and molecular dynamics simulation study
Author(s) -
Fathollahi Manoochehr,
AziziToupkanloo Hossein
Publication year - 2019
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.201800371
Subject(s) - thermite , reaxff , chemistry , energetic material , molecular dynamics , thermodynamics , differential scanning calorimetry , thermal decomposition , activation energy , autoignition temperature , ignition system , nano , non blocking i/o , kinetics , kinetic energy , combustion , materials science , composite material , computational chemistry , organic chemistry , explosive material , physics , interatomic potential , catalysis , quantum mechanics
In the experimental part of this study, thermal properties of the Al and NiO composites in micro‐ and nano‐sized Al are investigated. Differential scanning calorimetry (DSC) analysis of the onset temperatures of ignition, activation energy ( E a ), frequency factor ( A ), rate constant ( k ) , critical ignition temperature of thermal explosion ( T b ), and self‐accelerating decomposition temperature (T SADT ), as well as the thermodynamic parameters ( ΔS ≠ , ΔH ≠ , and ΔG ≠ ) are used to explore the thermal behavior and analyze the kinetics. Thermal analysis suggests that the mechanism is based on solid–solid diffusion and liquid–gas for the nano‐ and micro‐Al/NiO composite, respectively. Our results indicate that the incorporation of nano‐Al particles can significantly reduce the ignition temperature, E a , A , k , T b , and T SADT . In the second part of this work, molecular dynamics (MD) simulation is used to investigate the behavior of Al/NiO thermite reaction using the Reaxff force field to evaluate the experimental results. Theoretically, MD results show 1,154 K as the reaction ignition temperature, which is in reasonably good agreement with experimental temperature of 893°C (1,166 K). The radial distribution function (RDF) shows that no reaction occurs at 500 K but it is complete at 1,200 K.