Uncracked Gaseous Ammonia NH3 as a Powerful Nitriding Medium

This monograph describes aspects of uncracked ammonia NH3 gas as a powerful nitrdiding medium. Uncracked NH3 is NH3 gas with suppressed extent of dissociation from that in NH3 gas in dissociation equilibrium state in closed reaction chamber. Starting from pioneering works by Haegg on synthesis of mono-nitride MoN of Mo and by Lehrer on synthesis of (epsilon)-Fe2N of Fe, both published coincidentally in 1930, subsequent experimental attempts to use uncracked NH3 gas as a powerful nitriding medium to synthesize higher nitrides of metals that are difficult to be nitride in stable N2 gas environment are reviewed. Results of recent works using uncracked NH3 gas as a nitriding medium in the experiments done using concentrated solar beam as the reaction heat source are also described. Thermodynamic analysis results by Dr. Masahiro KATSURA demonstrating high capacity of NH3 and other tri-hydrides XH3 of nitrogen group elements (X = P, As and Sb) as hydriding agent are also described.