Characteristics of self-propagating reaction in TiN combustion synthesis

Abstract

The characteristics of the combustion synthesis of TiN are investigated through a self-propagating reaction of titanium powder compacts of specific packing density (40% to 60% theoretical one) in the presence of flowing nitrogen gas (0.01 m³ min⁻¹) under atmospheric pressure. It was found that the propagating velocity of the combustion wave became slower with increasing packing density. The conversion ratio of nitrided titanium increased with increasing packing density, and reached about 70% in the case of 60% densely packed compact covered with a quartz tube. However, in the case where nitrogen gas flowed from the centre bottom of the compact, the conversion ratio was almost independent of packing density. It is considered that the predominant factors for achieving higher conversion are the combustion wave velocity and temperature gradient in the high temperatures region behind the combustion front.