Relationship between Interfacial and Coating Fracture Toughnesses of Thermal Barrier Coating
Relationship between Interfacial and Coating Fracture Toughnesses of Thermal Barrier Coating
复制标题
DOI：
10.2472/jsms.69.863
复制
发表时间：
2020-12
期刊：
影响因子：
--
通讯作者：
Tomoya Tsuge;H. Waki;Kanta Adachi;Tomohiko Hojo
中科院分区：
文献类型：
--
作者：
Tomoya Tsuge;H. Waki;Kanta Adachi;Tomohiko Hojo
一种热障涂层(TBC)系统由基材、粘结层(BC)和顶层(TC：TBC)组成。涂层是用热喷涂的方法沉积的。TBC和BC之间的界面断裂韧性是重要的力学性能，因为它是进行损伤评估所必需的。TBC体系受热暴露影响，界面断裂韧性不仅受TBC韧性的影响，还受热暴露的影响。然而，由于很难进行准确的比较，关于界面与TBC韧性之间关系的研究很少。本研究的目的是探讨界面韧性与热障涂层韧性之间的关系。为此，我们使用相同的试件和相同的评估理论，使用压痕技术评估了热暴露TBC试件的两种韧性。结果表明，在中等温度下，两种涂层的界面断裂韧性均高于TBC断裂韧性。另一方面，涂层的TBC韧性逐渐接近高温下暴露的涂层的界面韧性。此外，处理温度越高，收敛速度越快。界面裂纹不是发生在严格界面上，而是发生在界面附近的热障涂层上。这些结果表明，界面韧性与涂层韧性基本相同，两者的变化是由TBC的烧结引起的。
A thermal barrier coating (TBC) system consists of a substrate, a bond-coat (BC), and a top-coat (TC: TBC). The coatings are deposited by thermal spraying. The interfacial fracture toughness between TBC and BC is important mechanical property because it is necessary for damage assessment. The TBC system suffers from thermal exposure, and the interfacial fracture toughness is changed by the thermal exposure as well as the TBC toughness. However, there are few studies on the relationship between the interfacial and TBC toughnesses due to the difficulty of accurate comparison. The purpose of this study is to investigate the relationship between interfacial and TBC toughnesses. For this purpose, we evaluated the two toughnesses of thermally exposed TBC specimens using an indentation technique with an identical specimen and identical evaluation theory. Our results revealed that the interfacial fracture toughness was higher than the TBC fracture toughness for both the coatings as-sprayed and exposed at a moderate temperature. On the other hand, the TBC toughness became to be close to the interfacial toughness for the coatings exposed at high temperatures. Additionally, the convergence rate became to be high by higher treatment temperature. The interfacial cracks occurred not at the strict interface but at the TBC near the interface. These results suggested that interfacial toughness was essentially identical to coating toughness and the changes in the two toughnesses were caused by sintering of the TBC.