Thermal decomposition of δ-MoN and ε-Fe2N synthesized under concentrated solar radiation in NH3 gas stream

•The decomposition of δ-MoN, ε-Fe2N was investigated by DSC.•δ-MoN underwent decomposition into γ-MoN and γ+β-Mo2N.•ε-Fe2N decomposed into γ’-Fe4N upon heating in Ar up to 700 °C.•γ’-Fe4N was fully converted into α-Fe when N2 was used as nitriding media.