Thermochemical interactions between calcium–magnesium–aluminosilicate (CMAS) glass and an environmental barrier coating of ytterbium disilicate (Yb2Si2O7) and ytterbium monosilicate (Yb2SiO5) were investigated. Top coats were deposited by plasma spray-physical vapor deposition onto silicon carbide substrates. CMAS powder was prepared as a glass and cast into a tape to yield a CMAS loading of ~29 mg/cm2. Samples were heat treated with CMAS at 1300 °C for 1–10 h or at 1400 °C for 1 h in air. Polished specimen cross-sections were characterized using scanning electron microscopy, X-ray diffraction, X-ray energy-dispersive spectroscopy, and transmission electron microscopy to evaluate resulting microstructures, phases, and compositions at CMAS/Yb2Si2O7 interfaces. Coatings exposed at 1300 °C—10 h and 1400 °C—1 h were fully infiltrated and compromised by CMAS. Dissolution of ytterbium silicate into molten CMAS followed by precipitation of cyclosilicate, silicocarnotite, and Yb2Si2O7 at 1300 °C and Yb2Si2O7 at 1400 °C enabled CMAS to effectively infiltrate top coats, rendering the predominantly Yb2Si2O7 coating ineffective at arresting molten CMAS degradation.

研究了钙镁铝硅酸盐（CMAS）玻璃与二硅酸y（Yb 2 Si 2 O 7）和单硅酸（Yb 2 SiO 5）的环境屏障涂层之间的热化学相互作用。通过等离子喷涂-物理气相沉积将面涂层沉积在碳化硅衬底上。将CMAS粉末制成玻璃杯，并浇铸成胶带，以使CMAS负载约为29 mg / cm 2。样品在1300°C的空气中用CMAS在1300°C热处理1–10 h或在1400°C进行热处理。使用扫描电子显微镜，X射线衍射，X射线能量色散光谱和透射电子显微镜对抛光的样品横截面进行表征，以评估在CMAS / Yb 2 Si 2 O 7界面产生的微观结构，相和组成。在1300°C–10 h和1400°C–1 h暴露的涂层被CMAS完全渗透并破坏了。镱硅酸盐到熔融CMAS的溶解，随后环硅酸盐，silicocarnotite的沉淀，和Yb 2的Si 2 ö 7在1300℃和Yb 2的Si 2 ö 7在1400°C下，CMAS可以有效渗透面涂层，从而使主要的Yb 2 Si 2 O 7涂层无法有效阻止熔融CMAS的降解。