Investigation on improving corrosion resistance of rare earth pyrosilicates by high-entropy design with RE-doping. (1st May 2022)

• Record Type: Journal Article
• Authors: Chen, Zeyu; Lin, Chucheng; Zheng, Wei; Zeng, Yi; Niu, Yaran
• Is Part Of: Corrosion science. Volume 199(2022)
• Publication Date: 2022-05-01
• Subjects: Environmental barrier coatings -- High-entropy pyrosilicates -- CMAS corrosion mechanisms -- Rare earth cations; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2022.110217
• Languages: English
• ISSNs: 0010-938X

Abstract

Abstract: To combine the advantages of the thermal expansion coefficient and excellent corrosion resistance to calcium-magnesium-alumino-silicate (CMAS), two types of high-entropy pyrosilicates ((Yb0.2 Y0.2 Lu0.2 Ho0.2 Er0.2 )2 Si2 O7 and (Yb0.25 Lu0.25 Ho0.25 Er0.25 )2 Si2 O7 ) and two single-component pyrosilicates (Yb2 Si2 O7 and Lu2 Si2 O7 ) were prepared by the solid-phase method. CMAS corrosion resistance test results showed that the high-entropy pyrosilicates that form a stable β phase could precipitate apatite (Ca2 RE8 (SiO4 )6 O2 ) more easily than Yb2 Si2 O7 and Lu2 Si2 O7 during the corrosion process to protect the block from CMAS. The results provide a theoretical basis for the selection of rare earth elements in high-entropy pyrosilicate according to the radius of different rare earth cation. Highlights: High mixing entropy caused the β-phase structure to move towards a low temperature. RE 3+ of the high-entropy pyrosilicates were evenly distributed on the atomic scale. RE 3+ ions with a large ionic radius are more likely to precipitate apatite from CMAS. (5RE1/5 )2 Si2 O7 and (4RE1/4 )2 Si2 O7 showed excellent CMAS corrosion resistance.