Corrosion behavior of Y2O3-doped mullite-ZrSiO4 coatings applied on C/C–SiC composites in the presence of moisture at temperatures of 1373–1773 K. Issue 8 (1st June 2020)

• Record Type: Journal Article
• Authors: Qian, Tianxiao; Zeng, Yi; Xiong, Xiang; Ye, Ziming; Lun, Huilin; Hu, Jinrun; Wang, Yalei; Zhang, Zhongwei; Yan, Changhai
• Is Part Of: Ceramics international. Volume 46:Issue 8(2020)Part B
• Page Start: 12861
• Page End: 12869
• Publication Date: 2020-06-01
• Subjects: Environmental barrier coating -- Commercial mullite -- Mullite-Y2Si2O7–ZrSiO4 coating -- Water vapor corrosion behaviour; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2020.01.124
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Commercial mullite powders show great potential for application in environmental barrier coatings. However, most of the commercial mullite powders contain amorphous silica, which produces volatile silicon hydroxide in hot steam. This leads to serious recession of mullite coatings in hot water vapor. In this study, a Y2 O3 -doped mullite-ZrSiO4 coating was fabricated on C/C–SiC composites using the slurry painting method. The addition of Y2 O3 resulted in the elimination of the residual silica and derived-cristobalite in the commercial mullite powder, leading to the formation of a stable mullite-Y2 Si2 O7 –ZrSiO4 coating. This indicates that Y2 O3 can efficiently enhance the phase stability of commercial mullite at high temperatures. In addition, the corrosion behaviours of Y2 O3 -doped mullite-ZrSiO4 coatings were investigated at 1373, 1573, and 1773 K in a 95% H2 O-5% O2 atmosphere. The coatings exhibited good corrosion resistance. The 15 mol% Y2 O3 coating showed a weight loss rate of 1.62 wt % when exposed to hot steam for 10 h at 1573 K. This value is only 1/8th of that of the uncoated sample. Moreover, ZrSiO4 improved the water corrosion resistance of the Y2 O3 -doped mullite-ZrSiO4 coatings at 1573 K.