Affiliation:
1. School of Metallurgical Engineering Xi'an University of Architecture and Technology Xi'an China
2. National Engineering Research Centre of Ceramic Matrix Composite Manufacture Technology Xi'an Golden Mountain Ceramic Composites Co., Ltd. Xi'an China
3. Key Laboratory for Liquid‐Solid Structural Evolution and Processing of Materials (Ministry of Education) School of Materials Science and Engineering Shandong University Jinan China
4. Science and Technology on Thermostructural Composite Materials Laboratory Northwestern Polytechnical University Xi'an China
Abstract
AbstractTwo structured ytterbium monosilicate environmental barrier coatings (Si/Yb2SiO5 and Si/mullite/Yb2SiO5) were prepared on SiC/SiC composites and their performance in wet oxygen at 1350°C was investigated. After 300 h of corrosion, coating peeling occurred for Si/Yb2SiO5–SiC/SiC, while it was intact for Si/mullite/Yb2SiO5–SiC/SiC system due to the mullite intermediate coating well alleviating the thermal expansion mismatched stress. During the assessment, Yb2SiO5 and mullite gradually densified, and a thin layer of ytterbium disilicates (Yb2Si2O7) was formed at their junction as a new protective layer, which pinned into the mullite layer and significantly improved their interface bonding strength and resistance against wet oxygen. The strength retention of SiC/SiC, Si/Yb2SiO5–SiC/SiC, and Si/mullite/Yb2SiO5–SiC/SiC was 64%, 72%, and 97%, respectively, after corrosion in wet oxygen at 1350°C/300 h. Their corrosion mechanism was proposed.
Subject
Materials Chemistry,Marketing,Condensed Matter Physics,Ceramics and Composites