The high-temperature (1500 °C) interactions of two promising dense, polycrystalline EBC ceramics, β-Yb₂Si₂O₇ and β-Sc₂Si₂O₇, with a calcia-magnesia-aluminosilicate (CMAS) glass have been explored as part of a model study. Unlike YAlO₃ and γ-Y₂Si₂O₇ in the accompanying Part I paper, little or no reaction is found between the Y-free EBC ceramics and the CMAS. In the case of β-Yb₂Si₂O₇, a small amount of reaction-crystallization product Yb-Ca-Si apatite solid solution (ss) forms, whereas none is detected in the case of β-Sc₂Si₂O₇. The CMAS glass penetrates into the grain boundaries of both EBC ceramics, and they both suffer from a new type of ‘blister’ cracking damage. This is attributed to the through-thickness dilatation-gradient caused by the slow grain-boundary-penetration of the CMAS glass. The success of a ‘blister’-damage-mitigation approach is demonstrated, where 1 vol% CMAS glass is mixed into the β-Yb₂Si₂O₇ powder prior to sintering. The CMAS-glass phase at the grain boundaries promotes rapid CMAS-glass penetration, thereby avoiding the dilatation-gradient.

高温（1500℃）的2相互作用有前途的致密的，多晶EBC陶瓷，β-镱₂的Si ₂ ö ₇和β-Sc合金₂的Si ₂ ö ₇，具有氧化钙-氧化镁-铝硅酸盐（CMAS）玻璃已作为模型研究的一部分进行了探索。不像YALO ₃和γ-Y ₂的Si ₂ Ó ₇在所附的第I部分纸，很少或没有反应的Y自由EBC陶瓷与CMAS之间找到。在的情况下，β-镱₂的Si ₂ ö ₇，反应结晶产物镱的Ca-Si的少量磷灰石固溶体（SS）形式的，而在β-Sc的情况下，没有检测到₂的Si ₂ ö ₇。CMAS玻璃渗透到两种EBC陶瓷的晶界中，并且它们都遭受新型的“起泡”裂纹损坏。这归因于由CMAS玻璃的缓慢的晶界渗透引起的全厚度膨胀梯度。一个“blister'损伤减缓方法的成功证明，其中，1体积％的玻璃CMAS混入β镱₂的Si ₂ ö ₇粉末在烧结之前。晶界处的CMAS玻璃相促进了CMAS玻璃的快速渗透，从而避免了膨胀梯度。