Influence of ignition parameters on micropyretic synthesis of NiAl compound

The influence of ignition parameters on micropyretic synthesis of NiAl compound is numerically investigated in this study. The numerical results show that either a lower ignition power or ignition from the middle of specimen increases the ignition time to start the reactions, further transferring the more thermal energy from the ignition spot to the other regions. Thus, the length of pre-heating zone before propagation and the starting propagation velocity at the ignition spot are correspondingly increased. Such increments in the zone length and the starting propagation velocity result in inhomogeneous structures and properties at the ignition spot. The numerical calculation shows that the percentages of the inhomogeneous structures can be reduced by increasing the ignition power. However, a higher ignition power also consumes the additional ignition energy to ignite the specimens. In addition, the effect of the ignition parameters on the length of pre-heating zone is magnified for the systems with higher thermal conductivity of reactants. (c) 2005 Elsevier B.V. All rights reserved.