盐雾-高温交替环境下NiCrAlY涂层的腐蚀行为  

Corrosion behavior of NiCrAlY coatings under alternating salt spray and high temperature environment

作　　者：丁航 吴旭东 黄婷 辛丽坡 付勇 谢云 DING Hang;WU Xudong;HUANG Ting;XIN Lipo;FU Yong;XIE Yun(School of Materials Science and Engineering,Nanchang Hangkong University,Nanchang 330063,China;Liyang Aero Power Co.,Ltd.,AECC,Guiyang 550014,China)

机构地区：[1]南昌航空大学材料科学与工程学院,南昌330063 [2]中国航发贵州黎阳航空动力有限公司,贵阳550014

出　　处：《航空材料学报》2024年第6期53-60,共8页Journal of Aeronautical Materials

基　　金：江西省重点研发计划项目(20232BBE50007);江西省自然科学基金项目(20224BAB214018)。

摘　　要：海洋环境服役的航空发动机在频繁启停过程中面临严重的常温盐雾-高温氧化交替引起的腐蚀问题。采用直流磁控溅射技术在GH4169高温合金表面制备一层均匀致密的Ni25Cr5AlY涂层,通过设计1000℃高温氧化、常温盐雾和常温盐雾-高温氧化交替的实验环境,利用X射线衍射(XRD)和扫描电子显微镜(SEM)分析腐蚀产物的成分和结构,对NiCrAlY高温防护涂层的腐蚀损伤行为开展研究。结果表明:在进行168 h的高温氧化实验后,Ni25Cr5AlY涂层表面生长了一层连续致密的Al_(2)O_(3)膜,抗氧化性能良好;在进行168 h的常温盐雾实验后,涂层表面因局部形成点蚀坑而变得粗糙不平;在进行168 h的常温盐雾-高温氧化交替实验后,涂层因氯的活性氧化腐蚀机制导致表面Al_(2)O_(3)膜发生降解生长Cr_(2)O_(3)膜,氧化膜疏松多孔且局部开裂导致涂层腐蚀损伤加速,涂层和基体发生内氧化;没有涂层保护的GH4169合金在经历相同的交替实验后则发生严重的腐蚀损伤,表面形成保护性较差的NiO膜,合金发生严重的内氧化,腐蚀产物大量剥落而显著减重。Corrosion problem resulting from alternating ambient salt spray and high temperature oxidation poses a great threat to the safe service of aircraft engine during frequent start-stop in marine environment.In the present study,Ni25Cr5AlY coating is prepared on top of GH4169 superalloy substrate by direct-current(DC)magnetron sputtering.Corrosion behavior of the Ni25Cr5AlY coating is systematically studied by designing three different test conditions:high temperature oxidation at 1000℃,ambient salt spray,and alternating ambient salt spray and high temperature oxidation.The phase constitution and morphology of the corrosion products are analyzed by X-ray diffraction(XRD)and scanning electron microscopy(SEM).The results indicate that after 168 h oxidation at 1000℃,the coating forms a dense and continuous Al_(2)O_(3)scale which resists well against the oxidizing environment,while the coating suffers from pitting locally after 168 h salt spray test.After 168 h exposure to alternating ambient salt spray and high temperature oxidation test,the Al_(2)O_(3)scale formed on the coating is damaged owing to the chlorine induced active oxidation mechanism,eventually resulting in Cr_(2)O_(3)scale formation.In addition,the Cr_(2)O_(3)scale is porous and cracks locally,which causes accelerated corrosion of the coating and internal oxidation of the coating and substrate.The corrosion degradation of the coating is accelerated under the synergistic effect of salt spray and high temperature oxidation.The GH4169 superalloy without the coating experiences severe scale spallation after 168 h exposure to the alternating test,featured by forming a poorly protective NiO scale with prevalent internal oxidation.

关 键 词：NICRALY涂层 海洋环境 盐雾腐蚀 高温氧化 常温盐雾-高温氧化交替 

分 类 号：V259[一般工业技术—材料科学与工程] TG174.4[航空宇航科学与技术—航空宇航制造工程]