Homogenizing role of hydrogen in the synthesis of multicomponent Carbohydrides and Nitridohydrides of transition metals in the combustion mode

This work presents the results of study of combustion with carbon of transition metals of IV, V and VI groups of the periodic system in atmospheres of argon, hydrogen, nitrogen and nitrogen-hydrogen mixture. The significance of hydrogen in the formation of single-phase products in the self-propagating high-temperature synthesis (SHS) mode was underlined. The combustion of carbon containing systems in argon resulted in the synthesis of two-phase carbides with FCC lattice. In contrary, the combustion of the same systems in hydrogen atmosphere leaded to the synthesis of single-phase carbo-hydrides. The products of combustion of transition metals in nitrogen atmosphere were the multiphase nitrogen-containing compounds. Their following re-ignition in hydrogen leaded to the synthesis of single-phase nitrido-hydrides. It was demonstrated that in all the studied systems, the combustion in hydrogen atmosphere leaded to the homogenized final synthesis products. The results of these processes were the formation of single-phase carbo- and nitrido-hydrides based on the metals of IV, V and VI groups. The presence of hydrogen in the crystal lattice of synthesized refractory carbides and nitrides facilitated easy dispersion of the compound to submicron sizes. After removal of hydrogen, the single phase structure was not violated. The described results may be of commercial value in the industry of refractory materials.