Mechanics and Mechanisms on Adhesion of Thermal Barrier Coating : Towards Improvement and Design of Thermal Fatigue Endurance.

热障涂层附着力的力学和机理：热疲劳耐久性的改进和设计。

基本信息

批准号：
15360046
负责人：
OKAZAKI Masakazu
金额：
$ 9.66万
依托单位：
Nagaoka University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

Thermal barrier coatings (TBCs) with high performance have been essential for next generation advanced gas turbines operating at extremely high temperatures. Towards improvement and design of thermal fatigue endurance of TBCs, a series of experimental works have been carried out to get basic understandings on the following articles : how the mechanical properties of ceramic top coat film in TBCs, especially elastic moduli, should be evaluated ; what effect(s) the process variables have ; how high is the adhesion strength of ceramic top coat with Ni-based superalloys substrate and how it should be evaluated ; and how high is the residual stress in TBCs and how it should be evaluated. Elastic stiffness of air plasma sprayed (APSed) YSZ (; ZrO2 stabilized by 8 wt. pct. Y2O3) top coat specimen, which is frequently used for thermal barrier coating (TBC) system for advanced gas turbines, was measured by employing the macro-, micro-, and nano-indentation methods. The elastic stiffness was measured, following the Oliver-Pharr method. It was shown that the elastic stiffness of the YSZ, as well as the microstructure, were significantly influenced by the spraying conditions employed. Especially the size of ceramic powders used were found to have the most pronounced effect. It was also shown that the elastic stiffness revealed significant size effect : that is, there were significant differences in elastic stiffness between the macro-, micro-, and nano-indentation methods. The above size effect was discussed, correlating with some relating phenomena during the indentation process : crackings, sink-in, pile-up and spalling ; as well as with the characteristic microstructures of the sprayed top coat. Based on these knowledge, special discussions have been made on which type of microstructure should be controlled to develop high performance TBCs and how it can be realized through a control of spraying process variables.

高性能热障涂层 (TBC) 对于在极高温度下运行的下一代先进燃气轮机至关重要。针对热障涂层热疲劳性能的改进和设计，开展了一系列的实验工作，对以下文章有了基本的认识：如何评价热障涂层陶瓷面漆膜的力学性能，特别是弹性模量；过程变量有什么影响；陶瓷面涂层与镍基高温合金基体的结合强度有多高以及如何评价； TBC 的残余应力有多高以及如何评估。空气等离子喷涂 (APSed) YSZ（；用 8 wt.% Y2O3 稳定的 ZrO2）面漆样本的弹性刚度，经常用于先进燃气轮机的热障涂层 (TBC) 系统，通过采用宏观、微米和纳米压痕方法。按照 Oliver-Pharr 方法测量弹性刚度。结果表明，YSZ 的弹性刚度以及微观结构受到所采用的喷涂条件的显着影响。尤其是所用陶瓷粉末的尺寸被发现具有最显着的影响。研究还表明，弹性刚度表现出显着的尺寸效应：即宏观、微观和纳米压痕方法之间的弹性刚度存在显着差异。讨论了上述尺寸效应，并结合压痕过程中的一些相关现象：裂纹、下陷、堆积和剥落；以及喷涂面漆的特征微观结构。基于这些知识，对应该控制哪种类型的微观结构来开发高性能热障涂层以及如何通过控制喷涂工艺变量来实现这一点进行了专门讨论。