Formation and oxidation behavior of refractory high-entropy silicide (NbMoTaW)Si2 coating. (15th April 2022)

• Record Type: Journal Article
• Authors: Kuang, Juan; Zhang, Ping; Wang, Qianqian; Hu, Zhenfeng; Liang, Xiubing; Shen, Baolong
• Is Part Of: Corrosion science. Volume 198(2022)
• Publication Date: 2022-04-15
• Subjects: Refractory high entropy alloy -- High entropy silicide -- Oxidation behavior; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2022.110134
• Languages: English
• ISSNs: 0010-938X

Abstract

Abstract: A single high-entropy silicide (NbMoTaW)Si2 coating was prepared on NbMoTaW refractory alloy by a halide-activated pack cementation process. The formation mechanism and growth kinetics of the (NbMoTaW)Si2 coatings were analysed. The oxidation behavior of the (NbMoTaW)Si2 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)Si2 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)Si2 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 SiO2 scale and the precipitation of WSi2 to suppress the interdiffusion of the silicide layer and the alloy substrate. Highlights: A refractory high-entropy silicide (NbMoTaW)Si2 coating was formed on the NbMoTaW RHEA. The formation mechanism and growth kinetics of the (NbMoTaW)Si2 coatings were analyzed. The (NbMoTaW)Si2 coating significantly improves the oxidation resistance of the NbMoTaW RHEA at 1300 ℃ in air.