ABSTRACT

This review critically examines the current understanding of calcia–magnesia–alumina–silicate (CMAS) degradation mechanisms and mitigation approaches in thermal and environmental barrier coatings. First, the review introduces case studies of field returned engine components exposed to CMAS attack, followed by fundamental aspects of CMAS-induced degradation. Understanding CMAS adhesion, infiltration, spallation mechanics, and thermochemical attack mechanisms is crucial to designing materials approaches to mitigate CMAS attack. CMAS mitigation strategies have focused on reactive approaches aimed at crystallising molten CMAS at the earliest stage possible to inhibit infiltration. Promising approaches are presented, starting with fundamental reaction kinetics studies, followed by the effects of microstructure in actual coatings systems. Salient results on coating systems tested in various burner rigs and a full engine test are presented to benchmark the success of various mitigation strategies. Lastly, several key future research areas are presented in order to provide a roadmap towards ‘sandphobic’ thermal and environmental barrier systems.

摘要

这篇综述批判性地考察了目前对热和环境屏障涂层中氧化钙-氧化镁-铝-硅酸盐 (CMAS) 降解机制和缓解方法的理解。首先，审查介绍了暴露于 CMAS 攻击的现场返回发动机组件的案例研究，然后是 CMAS 引起的退化的基本方面。了解 CMAS 粘附、渗透、散裂力学和热化学攻击机制对于设计减轻 CMAS 攻击的材料方法至关重要。CMAS 缓解策略侧重于反应性方法，旨在尽可能早地使熔融 CMAS 结晶以抑制渗透。提出了有前景的方法，从基本的反应动力学研究开始，然后是实际涂层系统中微观结构的影响。展示了在各种燃烧器设备中测试的涂层系统的显着结果和完整的发动机测试，以衡量各种缓解策略的成功与否。最后，提出了几个关键的未来研究领域，以提供通往“憎沙”热和环境屏障系统的路线图。