Fabrication and oxidation resistant behavior of plasma sprayed Si/Yb₂Si₂O₇/LaMgAl₁₁O₁₉ coating for C_f/SiC composites at 1673 K

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• 作者：Wenjuan Fan^a ; ^b ; Binglin Zou^b ; ^{zoubinglin@ciac.ac.cn" class="auth_mail" title="E-mail the corresponding author} ; Cunyan Fan^a ; ^b ; Ying Wang^b ; Xiaolong Cai^b ; Shunyan Tao^c ; Jiaying Xu^b ; Chunjie Wang^b ; Xueqiang Cao^d ; ^{xcao@whut.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Ling Zhu^a ; ^{zhulingster@gmail.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Cf/SiC composites ; Coatings ; Oxidation resistance ; Plasma sprayed
• 刊名：Ceramics International
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：43
• 期：1
• 页码：392-398
• 全文大小：2142 K

文摘

C_f/SiC composites were plasma sprayed with Yb₂Si₂O₇/LaMgAl₁₁O₁₉ coatings with and without Si bond layer. Microstructure and oxidation protection of the coatings at 1673 K were investigated. The results showed that the coatings have the same phase constituent as that of the powders and uniformly distributed on the substrate. The bonding interface between the coating and substrate with Si bond layer is better than that of without Si bond layer. After 15 cycles of heating at 1673 K for 90 min, the weight losses of the coated samples with and without Si bond layer were 2.54% and 21.89%, respectively, however, for the uncoated sample, its weight loss was up to 36.47%. To certain extent, the Si bond layer efficiently healed the porosity on the surface of substrate and relieved the mismatch of coefficient of thermal expansion (CTE) between the coating and substrate, and therefore significantly improved the oxidation protection of the coating. The difference of CTEs between the coating and substrate, the chemical reactions between the LaMgAl₁₁O₁₉ and Yb₂Si₂O₇ layers and the holes and cracks inside C_f/SiC composites were disadvantageous to the oxidation resistance of the coatings.