Oxidation behavior of γ/Mo2Ni3Si ternary metal silicide alloy

The oxidation behavior of Mo2Ni3Si based ternary metal silicide alloy toughened by small amount of nickel-base solid solution (γ) was investigated at 1173 K. The oxide scale was observed to have a duplex structure consisting of a top columnar NiO layer and an internal NiO-SiO2 mixed layer with continuous SiO2 formed at its base. The continuous SiO2 layer made a significant contribution to the low oxidation rate through preventing the diffusion of oxygen and Ni2+. While, the cracks existing in the oxide scale due to growth stress, thermal stress and volatilization of MoO3 provided rapid diffusion paths for oxygen and Ni2+ and deteriorated the alloy's oxidation resistance.