Rare earth silicate environmental barrier coatings (EBCs) are state of the art for protecting SiC ceramic matrix composites (CMCs) against corrosive media. The interaction of four pure rare earth silicate EBC materials Yb₂SiO₅, Yb₂Si₂O₇, Y₂SiO₅, Y₂Si₂O₇ and three ytterbium silicate mixtures with molten calcium‐magnesium‐aluminosilicate (CMAS) were studied at high temperature (1400°C). The samples were characterized by SEM and XRD in order to evaluate the recession of the different materials after a reaction time of 8 hours. Additionally, the coefficient of thermal expansion (CTE) was determined to evaluate the suitability of Yb silicate mixtures as EBC materials for SiC CMCs. Results show that monosilicates exhibit a lower recession in contact with CMAS than their disilicate counterparts. The recession of the ytterbium silicates is far lower than the recession of the yttrium silicates under CMAS attack. Investigation of the ytterbium silicate mixtures exposes their superior resistance to CMAS, which is even higher than the resistance of the pure monosilicate. Also their decreased CTE suggests they will display better performance than the pure monosilicate.

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纯稀土和混合稀土硅酸盐对钙镁铝硅酸盐（CMAS）的抗性：比较研究

稀土硅酸盐环境屏障涂料（EBC）是用于保护SiC陶瓷基复合材料（CMC）免受腐蚀介质影响的最新技术。四种纯稀土硅酸盐EBC材料Yb ₂ SiO ₅，Yb ₂ Si ₂ O ₇，Y ₂ SiO ₅，Y ₂ Si ₂ O ₇的相互作用并在高温（1400°C）下研究了三种硅酸y与熔融钙镁铝硅酸盐（CMAS）的混合物。样品通过SEM和XRD进行表征，以评估8小时反应时间后不同材料的回缩率。另外，确定热膨胀系数（CTE）以评估Yb硅酸盐混合物作为SiC CMC的EBC材料的适用性。结果表明，单硅酸盐与CMAS接触的退缩性低于二硅酸盐。硅酸的衰退远低于在CMAS攻击下硅酸钇的衰退。对硅酸混合物的研究揭示了它们对CMAS的优越抵抗力，甚至比纯单硅酸盐的抵抗力还高。