The Study of Ignition Parameters for Energy Efficient Processing of High Temperature Non-Oxide Ceramics by the Micropyretic Synthesis Route

Abstract

The influence of ignition parameters for energy efficient processing of high temperature non-oxide ceramics by the micropyretic synthesis route is studied numerically in this article. The simulation results show that a lower ignition power leads to longer ignition time to initiate reactions. An increase in the ignition time also increases the length of pre-heating zone before propagating, which further changes the initiate propagation velocity and oscillatory frequency of the temperature variations. Such changes in the initiate propagation velocity and temperature variations result in inhomogeneous structures at the ignition spot. The simulation also indicates that using a higher power to ignite the micropyretic reactions can lower the ignition time and further prevent the inhomogeneous structures from being formed at the ignition spot. However, more heat loss is noted to occur due to a high temperature gradient and the energy required to ignite the reaction. The numerical calculation indicates that there is a 20 % increase in the required energy and a 90% decrease in the required time to ignite the specimen when the ignition power is increased from 87.5 kJ/(g･s) to 962.5 kJ/(g ･s). In addition, the effect of the individual material property on ignition is also investigated.