Effects of reaction medium on combustion of the Zr–Nb–C system

Self-propagating high-temperature synthesis was used to study combustion of the Zr–Nb–C system in argon, nitrogen, and a nitrogen-hydrogen mixture. In combustion in argon a deviation from the carbon stoichiometry facilitates the mutual dissolution of the formed phases and leads to the formation of single-phase complex carbides. The homogenizing role of hydrogen in the formation of the complex combustion products of the Zr–Nb–C–N–H system was shown. It was found that there is competition among the effects of nitrogen, hydrogen, and carbon in this system. Concentration triangles of the Zr–Nb–C system were constructed which show the evolution of the phase composition of combustion products depending on the reaction medium.