GH3535合金表面渗铝层原位氧化工艺研究  

Study on the in-situ oxidation process of aluminizing layer formed on GH3535 superalloy

作　　者：梁超飞 刘卫[1] 张东勋[1] 王韡 王军 夏晓彬[1] LIANG Chaofei;LIU Wei;ZHANG Dongxun;WANG Wei;WANG Jun;XIA Xiaobin(Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China;University of Chinese Academy of Sciences,Beijing 100049,China;Shanghai Institute of Technology,Shanghai 201400,China)

机构地区：[1]中国科学院上海应用物理研究所,上海201800 [2]中国科学院大学,北京100049 [3]上海应用技术大学,上海201400

出　　处：《核技术》2023年第5期43-50,共8页Nuclear Techniques

基　　金：国家自然科学基金(No.11935011)资助。

摘　　要：高温工况下钍基熔盐堆中存在氚泄漏的风险,建立氚渗透屏障涂层有助于应对这一问题。采用包埋渗铝和原位氧化工艺,在GH3535合金表面制备了Al2O3/Ni-Al复合阻氚涂层,重点分析了氧化温度和真空度对氧化铝薄膜微观结构的影响。利用掠入射X射线衍射、扫描电子显微镜、透射电子显微镜等手段对氧化铝薄膜表面及截面的微观形貌、相构成进行了实验分析。实验结果表明:低氧分压能降低氧化铝薄膜的形成速度,促进形成更致密、表面平整的薄膜;高的氧化温度有利于形成α相氧化铝及更厚的氧化铝薄膜,但会大大增加表面缺陷。1.2 Pa真空度气氛、850℃氧化温度、72 h氧化时间是较优的原位氧化工艺参数,可以在GH3535合金基体表面获得性能较好的氧化铝薄膜,其相结构为γ和α相,厚度约为0.8μm,且表面致密无缺陷。[Background]Under high-temperature operating conditions,the tritium would be generated inside the core of thorium-based molten salt reactor(TMSR)and probably diffuse through the structural material into the environment.Establishing an Al2O3/Ni-Al composite tritium permeation barrier coating may help address this issue.[Purpose]This study aims to explore the optimal preparation process,especially the in-situ oxidation process.[Methods]The Al2O3/Ni-Al composite coating was prepared on the surface of GH3535 alloy by pack cementation aluminizing(PCA)followed by vacuum in-situ oxidation,and the effects of oxidation temperature and vacuum on the microstructure of Al2O3 films were analyzed by experiments.Grazing incidence X-ray diffraction(GIXRD),scanning electron microscopy(SEM),and transmission electron microscope(TEM),X-ray energy dispersive spectroscopy(EDS)were used to characterize the phase composition and crystal structure of the alumina film,as well as morphologies of the surface and cross-section.[Results]The experimental results show that the low oxygen partial pressure can increase the forming temperature of alumina film,but can form a more compact film with flat surface.Higher oxidation temperature is conducive to the formation of thicker alumina films,but also greatly increases the surface defects.[Conclusions]By in-situ oxidation process at 1.2 Pa-850℃-72 h,alumina thin films with good properties can be obtained on the surface of GH3535 alloy:The phase of film containsγandα,the thickness is about 0.8μm,and the surface is compact without defects.

关 键 词：钍基熔盐堆 氚控制 渗铝层 原位氧化 氧化铝薄膜 

分 类 号：TL99[核科学技术—核技术及应用]