CMAS degradation of EB-PVD TBCs: The effect of basicity
CMAS degradation of EB-PVD TBCs: The effect of basicity
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DOI：
10.1016/j.surfcoat.2015.03.009
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发表时间：
2015-05
影响因子：
5.4
通讯作者：
M. Craig;N. L. Ndamka;R. Wellman;J. Nicholls
中科院分区：
文献类型：
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作者：
M. Craig;N. L. Ndamka;R. Wellman;J. Nicholls
在未来的发动机设计中，航空航天燃气涡轮机发动机的涡轮机入口温度将需要增加，这是由于在减少可能对环境有害的排放物的同时提高燃料效率和功率的持续需求。目前，热障涂层（TBC）与冷却膜一起使用，以保护发动机硬件免受涡轮机和燃烧区内的高温影响。空气中的颗粒，如灰尘，沙子和火山灰，也被称为“CMAS”电子束物理气相沉积（EB-PVD）TBC的柱状、高孔隙率微结构，通常在高压涡轮机叶片上发现，使得它们特别容易受到CMAS熔融存款侵蚀。本文研究了改变熔融CMAS沉积物的化学成分对EB-PVD热障涂层退化机理的影响。本文确定了一个参数称为“碱度指数”，它可以用来评估这些熔融沉积物对热障涂层的严重性和损害。据信，预计在下一代航空发动机中将观察到更高的温度，再加上世界各地不同的沙尘化学，然后碱性驱动的TBC降解将变得更加普遍。
Turbine entry temperatures of aerospace gas turbine engines will need to increase in future engine designs due to a constant desire to improve fuel efficiency and power whilst decreasing emissions which may be environmentally harmful. At present, thermal barrier coatings (TBCs) are employed together with a cooling film to protect engine hardware from the high temperatures seen within the turbine and combustion zones. Airborne particles such as dust, sand and volcanic ash, otherwise termed ‘CMAS’ (calcium–magnesium–alumino-silicates) are ingested into the engine, where at the elevated temperatures, this deposit can melt and induce degradation of the TBC.The columnar, high porosity microstructure of electron-beam physical vapour deposited (EB-PVD) TBCs, typically found on high pressure turbine blades, makes them particularly susceptible to CMAS molten deposit attack. This paper investigates the effect of modifying the chemical composition of molten CMAS deposits on the degradation mechanisms of EB-PVD TBCs. This paper identifies a parameter termed “basicity index” which can be used to evaluate the severity and damage caused by these molten deposits to TBCs. It is believed that the higher temperatures expected to be observed in next generation aero-engines coupled with sand/dust chemistry varying around the world, and then basicity-driven TBC degradation will become more prevalent.