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Optimization of fatigue property of ceramic coating for next-generation gas turbine

新一代燃气轮机陶瓷涂层疲劳性能优化

基本信息

批准号：
09305048
负责人：
WATANABE Ryuzo
金额：
$ 6.72万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09305048/
关键词：
Functionally graded Materials High temperature material Heat shield coating Plasma sprayed film Thermal shock test Electron beam deposition Fracture mechanics Material design セラミックコーティング熱機械的性質

项目摘要

Thermal shock and thermal fatigue tests of a PSZ/NiCrAlY plasma-spray coating were carried out, and with fracture mechanical analysis thermal fatigue fracture mechanisms were estimated. On the basis of this estimation an optimum processing conditions for the plasma spraying of the heat insulation coating were determined with reference to the composition profiles and microstructure of the coated film. The optimized coatings were subjected to the cyclic burner heating test, and a detailed observation on the fracture during testing. Along with the fracture mechanical consideration and optimum process conditions and microstructure morphology were worked out, as presented as follows : (1) Different AE signals were observed for heating and cooling period of the thermal shock testing, which indicated the crack initiation and their propagation. (2) Graded structure was found to be effective to prolong the thermal fatigue life. (3) Under a smaller thermal lord small crack was observed to form in the graded layer, which was found to be effective to prolong the thermal fatigue life. (4) Insertion of alumina layer between ceramic overcoat and NiCrAlY bond coat effectively suppressed the oxidation of the bond coat, and this will avoid the oxidation damage which is often observed in the actual working circumstance of the gas turbine, and will bring about high performance of the ceramic coatings. The obtained results will be presented at the 5th International Symposium on Functionally Graded Materials at Colorado, USA.

对PSZ/NiCrAlY等离子喷涂涂层进行了热冲击和热疲劳试验，并结合断裂力学分析，对涂层的热疲劳断裂机理进行了分析。在此基础上，结合涂层的成分分布和微观结构，确定了等离子喷涂隔热涂层的最佳工艺条件。对优化后的涂层进行了燃烧器循环加热试验，并对试验过程中的断口进行了详细观察。沿着断裂力学的考虑，确定了最佳的工艺条件和组织形貌，具体如下：（1）在热震试验的加热和冷却阶段，观察到不同的声发射信号，表明裂纹的萌生和扩展。(2)梯度组织是提高热疲劳寿命的有效途径。(3)在较小的热负荷下，梯度层中会形成小裂纹，这对延长热疲劳寿命是有效的。(4)在陶瓷涂层和NiCrAlY粘结层之间插入氧化铝层，有效地抑制了粘结层的氧化，避免了燃气涡轮机实际工作中经常出现的氧化损伤，提高了陶瓷涂层的性能。所获得的结果将在美国科罗拉多举行的第五届功能梯度材料国际研讨会上发表。