摘要
目的开展镍基单晶高温合金DD6在950℃下的热盐腐蚀试验(95%Na2SO4+5%NaCl),探明涂盐量和涂盐方式(周期涂盐和单次涂盐)对DD6高温热腐蚀的影响规律和机理。方法结合扫描电子显微镜、X射线能量色散谱、X射线衍射等设备,对不同涂盐量及涂盐方式下DD6的表面及横截面形貌进行观察分析,分析不同涂盐量和涂盐方式下DD6的高温热腐蚀机理。结果DD6在950℃下主要发生碱性熔融热腐蚀,同时伴随氧化、硫化和氯化等过程。高温热腐蚀使得DD6合金表面生成的保护性氧化膜被熔融态的腐蚀介质破坏,导致O、S、Cl等外部元素通过氧化膜的缺陷进入DD6基体中,在合金的亚表面发生内氧化、内硫化以及内氯化反应,横截面上出现明显的腐蚀层,其主要由氧化物以及硫化物组成。随着热腐蚀的进行,DD6表面物质发生了剥蚀,沉积盐量的增加导致剥蚀现象越加严重,合金内部致密的组织结构也被破坏,横截面上出现了大量孔洞、裂纹等缺陷。在相同涂盐量下,周期涂盐法使得DD6的腐蚀程度高于单次涂盐法。结论DD6高温热腐蚀行为与涂盐量及涂盐方式密切相关,相同涂盐方式下,涂盐量越大,DD6热腐蚀更加严重。涂盐量一定时,周期涂盐法使得DD6的热腐蚀剧烈程度大于单次涂盐法,且DD6在上述热腐蚀条件下均发生剥蚀破坏。
This study delves into the high-temperature hot corrosion behavior of the Ni-based single-crystal superalloy DD6,employing a hot salt corrosion test(95wt.%Na2SO4+5wt.%NaCl)conducted at 950℃.The effects of deposition manner,i.e.,periodic deposition and single deposition,and salt amount on the corrosion mechanisms were studied.The experimental results revealed that the superalloy undergoes alkaline molten hot corrosionat the elevated temperature of 950℃.The protective surface oxide film was found to deteriorate to corrosion,resulting in internal oxidation,internal sulfidation,and internal chlorination in the subsurface of the superalloy.Notably,a discernible corrosion layer,primarily composed of oxides and chlorides,was observed.As the hot corrosion progresses,the surface substance of the superalloyexperienced spallation,with a more substantial deposition of salt leading to more severe spallation.The severity of high-temperature hot corrosion is intricately linked to both the amount and manner of salt deposition,where a higher salt quantity correlates with more pronounced corrosion.Comparative analysis indicated that the periodic deposition exacerbated the hot corrosion when contrasted with the single deposition manner.The consequential surface spallation resulting from hot corrosion has the potential to significantly compromise the structural integrity of the single-crystal superalloy.
作者
杨百顺
李彪
王思远
张腾
叶飞
YANG Bai-shun;LI Biao;WANG Si-yuan;ZHANG Teng;YE Fei(School of Aeronautics,Northwestern Polytechnical University,Xi'an 710072,China;School of Aeronautical Engineering,Air Force Engineering University,Xi'an 710038,China;Zhuzhou Air Force Land Transportation Representative Office,Hunan Zhuzhou 412002,China)
出处
《装备环境工程》
CAS
2023年第12期10-19,共10页
Equipment Environmental Engineering
基金
国家自然科学基金(12072272)
重点实验室基金(2022-xxxx-LB-020-04)。
关键词
镍基单晶高温合金DD6
涂盐量
涂盐法
热腐蚀
腐蚀层
氧化层
内硫化层
Nickel-based single crystal superalloy DD6
salt deposition amount
salt deposition manner
hot corrosion
corrosion layer
oxide layer
internal sulfide layer
