plasma spraying

oxidation behavior

sic coating

oxide

bond coat

carbon carbon composites

aluminide coating

oxidation resistance

coatings

oxide layer

Corrosion Science

A single high-entropy silicide (NbMoTaW)Si 2 coating was prepared on NbMoTaW refractory alloy by a halide-activated pack cementation process. The formation mechanism and growth kinetics of the (NbMoTaW)Si 2 coatings were analysed. The oxidation behavior of the (NbMoTaW)Si 2 coatings was investigated at 1300 ℃ for 24 h in air. The results showed that the high entropy effect and sluggish effect of the high-entropy NbMoTaW alloy makes it form a single-phase silicide (NbMoTaW)Si 2 during the Si diffusion growth process. The lattice distortion effect of substrate provides a channel for the diffusion of Si to accelerate its diffusion rate. The (NbMoTaW)Si 2 coating effectively protects the NbMoTaW alloy from oxidation at 1300 ℃. The oxidation resistance of the coating is attributed to the preferential oxidation of Si to produce a dense continuous SiO 2 scale and the precipitation of WSi 2 to suppress the interdiffusion of the silicide layer and the alloy substrate. • A refractory high-entropy silicide (NbMoTaW)Si 2 coating was formed on the NbMoTaW RHEA. • The formation mechanism and growth kinetics of the (NbMoTaW)Si 2 coatings were analyzed. • The (NbMoTaW)Si 2 coating significantly improves the oxidation resistance of the NbMoTaW RHEA at 1300 ℃ in air.

Formation and oxidation behavior of refractory high-entropy silicide (NbMoTaW)Si2 coating