LAUSR

Abstract Mo Re duplex film has been electrodeposited from aqueous solution innovatively and then applied to fabricate protective silicide coating for the Nb Ti Si based alloy successively. The XRD, SEM and EDS results indicated the formation of MoSi2/ReSi2/NbSi2 compound coating after halide reactivated pack cementation (HAPC) treatment. Pesting oxidation of MoSi2 layer was suppressed and the Nb Ti Si based alloy was effectively protected at 800 °C with a mass gain of 0.48 mg cm−2 after oxidation for 100 h. At 1250 °C, continuous mass gain was observed with a mass gain of 2.6 mg cm−2 after exposure of 10 h. The synergistic combination of MoSi2 and NbSi2 layer enabled admirable protection of the substrate, in which MoSi2 layer worked as the major anti-oxidation coating and the NbSi2 layer could be a reservoir for Si. The contrast experiments indicate that ReSi2 layer could improve the integrity and adherence of MoSi2 layer, reduce the outward diffusion of alloying elements and oxidation of NbSi2 layer, and then improve oxidation resistance of the compound coating ultimately.