Environmental barrier coatings (EBCs) protect advanced ceramics and ceramic matrix composites (CMCs) from oxidation and corrosion in gas turbine engine environments. Foreign object damage (FOD), where debris impact the protective coatings, is a critical hazard which limits the turbine durability. Despite previous efforts to understand FOD in EBCs, a detailed understanding of the fundamental transient damage mechanisms is still lacking. In the current work, the real‐time FOD behavior of a mullite/ silicon EBC was visualized via a dynamic synchrotron X‐ray source in phase contrast imaging (PCI) configuration. Prior to the in situ FOD experiments, the microstructure and composition of the coating were, respectively, characterized using a scanning electron microscope (SEM) and X‐ray diffraction (XRD). The variation in the properties of the debris was modeled by~1.5mm diameter partially stabilized zirconia (PSZ) and silicon nitride (Si₃N₄) spheres. A modified light‐gas gun setup, synchronized with the X‐ray beam, was used to propel the projectiles at velocities ranging between 300 and 355ms⁻¹. Coated samples were impacted under a fully backed support configuration and at normal incidence. Coating penetration and delamination, as well as projectile deformation at the bond coat resulted for FOD by PSZ spheres. Comparatively, projectile fracture, with subsequent rebound of fragments, as well as complete coating penetration and delamination at the substrate interface occurred for FOD by Si₃N₄ spheres. Only cone cracking was observed for FOD by PSZ spheres, whereas back surface cracking was present for both projectile types. The driving forces for the observed damage mechanisms are qualitatively assessed.

中文翻译：

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环保涂层碳化硅（SiC）陶瓷中异物损坏（FOD）的原位表征

环境阻挡涂层（EBC）保护高级陶瓷和陶瓷基复合材料（CMC）在燃气轮机环境中免受氧化和腐蚀。异物损坏（FOD）是碎片危及防护涂层的重要危险，它限制了涡轮机的使用寿命。尽管先前曾努力了解EBC中的FOD，但仍缺乏对基本瞬时破坏机理的详细了解。在当前的工作中，通过相衬成像（PCI）配置中的动态同步加速器X射线源可视化了莫来石/硅EBC的实时FOD行为。在原位FOD实验之前，分别使用扫描电子显微镜（SEM）和X射线衍射（XRD）对涂层的微观结构和成分进行表征。₃ N ₄）个球体。与X射线束同步的改进型轻型气炮装置用于以300至355ms ^-1的速度推进弹丸。涂覆的样品在完全支撑的支撑结构下且在垂直入射时受到影响。PSZ球的FOD导致涂层的渗透和分层以及粘结层的弹丸变形。相比之下，Si ₃ N ₄对FOD的射弹断裂，随后的碎片反弹以及完全的涂层渗透和在基材界面的分层都发生了领域。PSZ球体仅观察到FOD的锥形裂纹，而两种弹丸类型均存在背面裂纹。定性评估观察到的损坏机制的驱动力。