Combustion metal nitride synthesis

Recently, studies from outside the Soviet Union have started to appear in the literature. In the US, Holt and Kingman17 reported the synthesis of transition metal nitrides not from gas-solid combustion reactions, but by using sodium azide as a solid source of nitrogen, according to the scheme ... 

Combustion synthesis of transition metal nitrides an overview 233... 

Combustion synthesis of metal nitrides from a solid nitrogen source was first investigated by Petrov in 1975.32 He used barium azide (Ba2N6) powder for the synthesis of TiN and Mg3N2. Holt, in 1983,33 reported the synthesis of TiN by using sodium azide (NaN3)as the solid nitrogen source. 

Hlavacek and co-workers [32] have simulated the synthesis of refractory metal nitrides by adiabatic combustion. The reactions involved occur at 2500... 

In the field of high-temperature combustion synthesis, metals have been reacted with nitrogen, both in the gaseous and liquid phases, to form refractory nitrides [2], In most cases, this nitriding process is heterogeneous. 

A theoretical analysis of combustion synthesis of refractory nitrides was presented by Munir and Holt in 1987.37 They predicted the existence of an activation energy due to chemical reaction or mass-transport. Glassman et al. in 1987,38 in their thermodynamic analysis of TiN formation, examined the possibility of creating TiN by a self-sustained reaction of the metal particles and nitrogen gas in a rocket motor. They reported that for the stoichiometric ratio of 0.5 mole N2/mole titanium, the reaction has... 

Detailed experimental studies on these gas-solid combustion reactions reveal the dependence of combustion and propagation characteristics, like front propagation velocity, combustion temperature and degree of conversion, on operating parameters like nitrogen pressure, particle size and morphology of the reactant metal and dilution of the gas and solid phases. From these studies the optimum synthesis conditions for a variety of nitrides are determined and information about the mechanisms of several gas-solid combustion reactions is obtained. With the aid of combustion theory, the apparent values of activation energy for several nitridation reactions are calculated from measured combustion characteristics. 

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