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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.

具有高性能的热障涂层（TBCs）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，进行了一系列的试验研究，对热障涂层陶瓷涂层的力学性能，特别是弹性模量如何评价，工艺参数对涂层热疲劳性能的影响，涂层热疲劳性能的评价等问题，取得了初步的认识。陶瓷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，热障涂层中的残余应力有多高以及如何评价。空气等离子体喷涂（APS）的YSZ（ZrO 2）的弹性刚度由8 wt.便士采用宏观、微观和纳米压痕法对先进燃气轮机热障涂层（TBC）中常用的氧化钇（Y2 O3）涂层试样进行了测试。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，显着影响所采用的喷涂条件。特别是所用陶瓷粉末的尺寸被发现具有最显著的效果。结果还表明，弹性刚度揭示了显着的尺寸效应：即，有显着差异的弹性刚度之间的宏观，微观和纳米压痕方法。讨论了上述尺寸效应与压痕过程中的一些相关现象：开裂、陷进、堆积和剥落，以及喷涂顶层的特征显微结构之间的关系。基于这些知识，特别讨论了应控制哪种类型的微观结构以开发高性能热障涂层，以及如何通过控制喷涂工艺参数来实现。