摘要
目的提高YSZ涂层的服役寿命。方法采用火焰喷涂和等离子喷涂的方法,在GH4169高温合金上分别制备Ni CoCrAlY粘结层和8YSZ陶瓷层。在制备陶瓷层之前,通过低压喷砂的方法对粘结层表面进行处理,改变粘结层的表面粗糙度。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、3D测量激光显微镜,表征涂层的物相、微观形貌和表面粗糙度。使用马弗炉进行1100℃的热震实验,表征YSZ涂层的热震性能。结果通过喷涂方法制备的粘结层,表面较为粗糙,喷砂处理后,有效地改善了表面情况,表面粗糙度下降了1~3μm。随着热震实验的进行,陶瓷层和粘结层中间形成的热生长氧化物(TGO)不断增厚。喷砂处理后,涂层的氧化速率降低。热震实验后,涂层边缘处会萌生微裂纹,随着裂纹的累积扩展,最终贯通,形成局部的涂层剥离。失效前后,YSZ没有相变发生。结论涂层失效多发生在TGO界面处,粘结层的高温氧化引起TGO层生长增厚,会导致涂层的失效。平整的TGO生长界面可以减少接触面,降低粘结层的氧化速率。平整界面可以避免局部起伏造成的TGO过度生长。经过表面喷砂处理改善粘结层粗糙度的涂层,具有更优异的抗热震性能。TGO层的形成和生长,容易导致微裂纹的萌生和扩展。粘结层表面处理后,能够为TGO的形成和生长提供相对平整的界面,有效提高TGO的质量,进而提高涂层的抗热震性能。
The effect of the surface treatment of the bonding layer on the thermal cycle life of the YSZ coating was studied.Flame spraying and plasma spraying were used to prepare NiCoCrAlY bonding layer and 8YSZ ceramic layer on GH4169 superalloy.Before preparing the ceramic layer,the surface of the bonding layer is treated by low-pressure sandblasting to change the surface roughness of the bonding layer.X-ray diffractometer(XRD),scanning electron microscope(SEM),3D measuring laser microscope were used to characterize the phase,microscopic morphology and surface roughness of the coating.Muffle furnace was used to perform a thermal cycle experiment at 1100℃to characterize the thermal shock performance of the YSZ coating.The surface of the adhesive layer prepared by spraying method is rough,and the surface condition is effectively improved after sandblasting.The surface roughness decreases by 1~3μm.The thermal growth oxide(TGO)formed between the ceramic layer and the bonding layer increases during the thermal shock test.The oxidation rate of the sandblasted coating is reduced.After the thermal shock test,microcracks appeared at the edge of the coating,and with the accumulation and expansion of the cracks,the coating peeled.There was no phase transition in YSZ before and after coating failure.The coating failure occurred at the TGO interface.The high temperature oxidation of the adhesive layer caused the growth and thickening of the TGO layer,which lead to the failure of the coating.The relatively smooth interface can reduce the contact area and reduce the oxidation rate of the adhesive layer.Smooth interface can avoid excessive growth of TGO.The coating with sandblasted surface has higher thermal shock resistance.
作者
李国浩
巴德纯
倪岩松
谭帧
陈红斌
杜广煜
LI Guo-hao;BA De-chun;NI Yan-song;TAN Zhen;CHEN Hong-bin;DU Guang-yu(School of Mechanical Engineering&Automation,Northeastern University,Shenyang 110819,China;Institute of Technology,Shenyang Radio and TV University,Shenyang 110004,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2021年第7期310-317,336,共9页
Surface Technology
基金
国家重点研发计划课题(2020YFB2007804)。
