Dynamic behaviour and chemical mechanism in the self-propagating high-temperature reaction between Zr powders and oxygen gas

Self-Propagating High-Temperature Synthesis of Intermetallic Compounds: A Computer Simulation Approach to the Chemical Mechanisms

“…Kinetics. To describe the time evolution of an SHS process we rely on a computational method described in previous papers. − To give here a brief summary, the method is based on the uncoupling between micro- and macrokinetic aspects. The microkinetic treatment describes the behavior of the system at the level of the grains of the solid phases involved in the various phase transformations and chemical reactions.…”

“…The aim of the present work is to describe a particular implementation of a flexible simulation method for investigating the chemical mechanisms of SHS processes and to present its first results. The general guidelines of the method (with application to the SHS between Zr metal and oxygen gas) have been presented in previous papers, , whereas the chemistry of the model has been rewritten to account for the reactivity in the Al/Ni system, as described in the following section.…”

Dynamic behavior in self-propagating high-temperature synthesis of intermetallic compounds

“…It is particularly interesting to search for transversal instabilities (non-planar and time dependent shapes of the propagation front) in systems showing steady propagation along the longitudinal axis. In addition to our usual finite differences (FD) one-dimensional (1D) approach [18][19][20][21][22], we have therefore implemented a 3D approach based on a commercial finite volume (FV) engine [25] linked to our model specific chemical routines.…”

“…For a comprehensive account of the computational method, we make here reference to previous works [18][19][20][21][22] on the SHS reaction of solid Zr in O 2 gas to produce the oxide ZrO 2 . For this reaction, the simulations have shown a route to chaos closely resembling the previously referred sequence of bifurcations found by Bayliss and Matkowsky [14][15][16][17].…”

“…For these reasons, the present authors have developed a general purpose numerical method for investigating SHS processes [18][19][20][21][22], The method is based on the uncoupling of macro-kinetics and micro-kinetics, where the former aspect takes care of heat transport as described by Fourier equation, while the latter one models chemical and phase transformations at the level of the grains of the interacting particles, and can involve at will many different reaction steps and different mechanism for each step.…”