REACTION FRONT PROPAGATION CHARACTERISTICS IN NON-CATALYTIC EXOTHERMIC GAS-SOLID SYSTEMS

Abstract Synthesis of transition metal nitrides and hydrides can be accomplished in the self propagating high temperature regime. A one dimensional model is proposed to study the effects of various operating parameters on the stability of the combustion front, to which gaseous oxidizer is fed by a process of filtration through the permeable solid. Different propagation phenomena can exist depending on the pressure of the gaseous reactant. The stability criteria derived for solid-solid systems can be extended for gas-solid systems at high pressures. At very low pressures filtration combustion is always stable. Systems which show unstable front propagation under adiabatic conditions have been observed to become more unstable due to heat losses.