目的 提高PS-PVD沉积7YSZ热障涂层的抗高温氧化性能.方法 采用等离子喷涂-物理气相沉积(PS-PVD)分别在未预处理和预处理(抛光+预氧化)的粘结层表面制备了柱状结构7YSZ热障涂层,并在大气环境下测试了柱状结构7YSZ热障涂层的950℃静态高温氧化性能.利用扫描电子显微镜、X射线衍射仪、能谱仪对高温氧化过程中的陶瓷层/粘结层界面形貌、TGO层结构演变进行表征.结果 粘结层的抛光处理能够降低表面几何受力不均匀部位,抑制陶瓷层/TGO/粘结层界面处微裂纹的产生,同时粘结层的预氧化处理形成的薄而连续的TGO层能有效降低TGO的生长速度,抑制陶瓷层-粘结层之间的元素互扩散.柱状结构7YSZ涂层的高温氧化动力学曲线符合Wagner抛物线规律,粘结层未预处理和预处理的7YSZ热障涂层的氧化速率常数分别为0.101×10-12 cm2/s和0.115×10-13 cm2/s.结论 粘结层预处理能有效改善等离子物理气相沉积7YSZ热障涂层的抗氧化性能.
The work aims to improve resistance to high temperature oxidation of 7YSZ thermal barrier coating deposited by plasma spray-physical vapor deposition.The columnar structure 7YSZ thermal barrier coatings (TBCs) were prepared by plasma spray-physical vapor deposition (PS-PVD) on pretreated (polishing+pre-oxidation) and un-pretreated bond coat surfaces,respectively.The static resistance to high temperature oxidation of 7YSZ thermal barrier coatings was tested in atmospheric environment at 950 ℃.Interfacial morphology of the ceramic layer/bond coat as well as structure evolution of TGO layer during high-temperature oxidation process were characterized by virtue of scanning electron microscope (SEM),X-ray diffractometer and (XRD) and energy dispersive spectrometer (EDS).Polishing of bond coats could reduce parts subject to non-uniform geometric stress and inhibit the formation of micro-crack at the interface of ceramic layer/TGO/bond coats.Meanwhile,the thin and continuous TGO layer formed as a result of pre-oxidation treatment of bond coats could effectively reduce the growth rate of TGO and inhibit the element interdiffusion between ceramic layer and bond coats.The isothermal oxidation kinetic curve of columnar 7YSZ thermal barrier coatings conformed to Wagner parabolic law.The oxidation rate constant of 7YSZ coatings with bond coats pretreated and un-pretreated was 0.101 × 10-12 cm2/s and 0.115 × 10-13 cm2/s,respectively.The pretreated of bond coats can effectively improve the oxidation resistance of 7YSZ thermal barrier coating deposited by plasma spray-physical vapor deposition.
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