Calcium-magnesium-alumina-silicate (CMAS) resistance characteristics of LnPO₄ (Ln = Nd, Sm, Gd) thermal barrier oxides

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• 作者：Feng Wang^a ; ^b ; Lei Guo^a ; ^b ; ^c ; ^{glei028@tju.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; ^{glei028@163.com" class="auth_mail" title="E-mail the corresponding author} ; Caimei Wang^a ; ^b ; Fuxing Ye^a ; ^b ; ^c ; ^{yefx@tju.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Rare-earth phosphates ; Thermal barrier coatings (TBCs) ; Calcium-magnesium-alumina-silicate (CMAS) ; Apatite
• 刊名：Journal of the European Ceramic Society
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：37
• 期：1
• 页码：289-296
• 全文大小：3611 K

文摘

Calcium-magnesium-alumina-silicate (CMAS) attack has been considered as a significant failure mechanism for thermal barrier coatings (TBCs). As a promising series of TBC candidates, rare-earth phosphates have attracted increasing attention. This work evaluated the resistance characteristics of LnPO₄ (Ln = Nd, Sm, Gd) compounds to CMAS attack at 1250 °C. Due to the chemical reaction between molten CMAS and LnPO₄, a dense, crack-free reaction layer, mainly composed of Ca₃Ln₇(PO₄)(SiO₄)₅O₂ apatite, CaAl₂Si₂O₈ and MgAl₂O₄, was formed on the surface of compounds, which had positive effect on suppressing CMAS infiltration. The depth of CMAS penetration in LnPO₄ (Ln = Nd, Sm, Gd) decreased in the sequence of NdPO₄, SmPO₄ and GdPO₄. GdPO₄ had the best resistance characteristics to CMAS attack among the three compounds. The related mechanism was discussed based on the formation ability of apatite phase caused by the reaction between molten CMAS and LnPO₄.