scholarly journals Microstructure and Composition Evolution of a Fused Slurry Silicide Coating on MoNbTaTiW Refractory High-Entropy Alloy in High-Temperature Oxidation Environment

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3592
Author(s):  
Jiesheng Han ◽  
Bo Su ◽  
Junhu Meng ◽  
Aijun Zhang ◽  
Youzhi Wu
Keyword(s):  
High Temperature ◽  
Oxide Layer ◽  
Silicon Content ◽  
High Temperature Oxidation ◽  
Layer Structure ◽  
High Entropy Alloy ◽  
Silicide Coating ◽  
Temperature Oxidation ◽  
High Entropy ◽  
Silicide Layer

In this paper, the Si-20Cr-20Fe coating was prepared on MoNbTaTiW RHEA by a fused slurry method. The microstructural evolution and compositions of the silicide coating under high-temperature oxidation environment were studied. The results show that the silicide coating could effectively prevent the oxidation of the MoNbTaTiW RHEA. The initial silicide coating had a double-layer structure: a high silicon content layer mainly composed of MSi2 as the outer layer and a low silicon content layer mainly contained M5Si3 as the inner layer. Under high-temperature oxidation conditions, the silicon element diffused from the silicide coating to the RHEA substrate while the oxidation of the coating occurred. After oxidation, the coating was composed of an outer oxide layer and an inner silicide layer. The silicide layer moved toward the inside of the substrate, led to the increase of its thickness. Compared with the initial silicified layer, its structure did not change significantly. The structure and compositions of the oxide layer on the outer surface strongly depended on the oxidation temperature. This paper provides a strategy for protecting RHEAs from oxidation at high-temperature environments.

scholarly journals Microstructure and Composition Evolution of a Fused Slurry Silicide Coating on MoNbTaTiW Refractory High-entropy Alloy in High-temperature Oxidation Environment

2020 ◽  
Author(s):  
Jiesheng Han ◽  
Bo Su ◽  
Junhu Meng ◽  
Aijun Zhang ◽  
Youzhi Wu
Keyword(s):  
High Temperature ◽  
Oxide Layer ◽  
Oxidation Resistance ◽  
Silicon Content ◽  
High Temperature Oxidation ◽  
High Entropy Alloy ◽  
Silicide Coating ◽  
Temperature Oxidation ◽  
High Entropy ◽  
Silicide Layer

The poor oxidation resistance of refractory high-entropy alloys (RHEAs) is a major obstacle for their use in high-temperature engineering applications. Anti-oxidation coating technology is an effective method for improving the oxidation resistance. In this paper, the Si-20Cr-20Fe coating was prepared on MoNbTaTiW RHEA by a fused slurry method. The microstructural evolution and compositions of the silicide coating under high-temperature oxidation environment were studied. The results show that the silicide coating could effectively prevent the oxidation of the MoNbTaTiW RHEA. The initial silicide coating had a double-layer structure; a high silicon-content layer mainly composed of MSi2 as the outer layer and a low silicon-content layer mainly contained M5Si3 as the inner layer. Under high-temperature oxidation conditions, the silicon element diffused from the silicide coating to the RHEA substrate while the oxidation of the coating occurred. After oxidation, the coating was composed of an outer oxide layer and an inner silicide layer. The silicide layer moved toward the inside of the substrate, led to the increase of its thickness. Compared with the initial silicified layer, its structure did not change significantly. The structure and compositions of the oxide layer on the outer surface strongly depended on the oxidation temperature. This paper provides a strategy for protecting RHEAs from oxidation at high-temperature environments.

scholarly journals High Temperature Oxidation Behavior of an Equimolar Cr-Mn-Fe-Co High-Entropy Alloy

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4259
Author(s):  
Lin Wang ◽  
Quanqing Zeng ◽  
Zhibao Xie ◽  
Yun Zhang ◽  
Haitao Gao
Keyword(s):  
High Temperature ◽  
Oxide Layer ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
High Entropy Alloy ◽  
Spinel Type ◽  
Temperature Oxidation ◽  
Outward Diffusion ◽  
High Entropy ◽  
High Temperature Oxidation Behavior

The oxidation behavior of an equimolar Cr-Mn-Fe-Co high-entropy alloy (HEA) processed by 3D laser printing was investigated at 700 °C and 900 °C. The oxidation kinetics of the alloy followed the parabolic rate law, and the oxidation rate constant increased with the rising of the temperature. Inward diffusion of oxygen and outward diffusion of cations took place during the high-temperature oxidation process. A spinel-type oxide was formed on the surface, and the thickness of the oxide layer increased with the rising of experimental temperature or time. The exfoliation of the oxide layer took place when the test was operated at 900 °C over 12 h. During oxidation tests, the matrix was propped open by oxides and was segmented into small pieces. The formation of loose structures had great effects on the high-temperature oxidation resistance of the HEA.

scholarly journals High temperature oxidation of non equi-atomic Al5Cr12Fe35Mn28Ni20 high entropy alloy

2021 ◽  
Author(s):  
Mayar M. Ali ◽  
Sanaa Said Abd Elmoamen ◽  
Mohamed A.H. Gepreel ◽  
Hafiz A. Ahmed ◽  
Fawzi A. Elrefaie
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
High Entropy Alloy ◽  
Temperature Oxidation ◽  
High Entropy

scholarly journals Effect of microalloying with silicon on high temperature oxidation resistance of novel refractory high-entropy alloy Ta-Mo-Cr-Ti-Al

2017 ◽  
Vol 35 (1-3) ◽  
pp. 168-176 ◽  
Author(s):  
Franz Müller ◽  
Bronislava Gorr ◽  
Hans-Jürgen Christ ◽  
Hans Chen ◽  
Alexander Kauffmann ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
High Entropy Alloy ◽  
Temperature Oxidation ◽  
High Entropy
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