两种热处理状态的镍基单晶高温合金在900℃下(Na_(2)SO_(4)+NaCl)混合盐中热腐蚀行为研究  

Hot Corrosion Behavior of a Nickel Based Single Crystal High Temperature Alloy Subjected to Different Heat Treatments

作　　者：张金龙 付广艳[1] 宁礼奎[2] 刘恩泽[2] 谭政[2] 佟健[2] 郑志[2] ZHANG Jinlong;FU Guangyan;NING Likui;LIU Enze;TAN Zheng;TONG Jian;ZHENG Zhi(School of Mechanical and Power Engineering,Shenyang University of Chemical Technology,Shenyang 110142,China;Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)

机构地区：[1]沈阳化工大学机械与动力工程学院,沈阳110142 [2]中国科学院金属研究所,沈阳110016

出　　处：《中国腐蚀与防护学报》2024年第6期1625-1632,共8页Journal of Chinese Society For Corrosion and Protection

基　　金：国家重点研发计划(2022YFB3705004)。

摘　　要：本文对完全热处理(CH)和完全热处理后长期时效(CH-LA)的两种热处理状态的镍基单晶高温合金涂覆75%Na_(2)SO_(4)+25%NaCl混合盐膜后进行900℃热腐蚀实验;并利用金相显微镜(OM)、扫描电子显微镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)等手段,对合金热腐蚀100 h后的表面形貌、物相组成、元素分布等进行分析,探讨了合金的热腐蚀机理。结果表明:CH样品γ基体上均匀分布着具有良好立方度的细小γ'相;CH-LA样品γ'相产生变形和粗化,而且析出了球状、针状和短棒状的TCP相。两种热处理状态的镍基单晶高温合金的腐蚀动力学曲线均近似抛物线或分段抛物线,CH样品腐蚀速率相对较小,腐蚀膜剥落轻微,表面形成了连续的Al_(2)O_(3)外氧化膜,内层区发生Al内氧化和Cr、Ni的内硫化;CH-LA样品,腐蚀速率相对大,表面腐蚀产物剥落明显,表面形成了较厚的复合氧化物层及极薄的Al_(2)O_(3)层,同时也形成了Al的内氧化和Cr、Ni的内硫化区。A nickel based single crystal high-temperature alloy was subjected to two different heattreatments,namely complete heat treatment(CH)and long-term aging after complete heat treatment(CH-LA).Then their hot corrosion behavior beneath a 75%Na_(2)SO_(4)+25%NaCl mixed salt film in air at 900℃ was studied by means of metallographic microscopy(OM),scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),and X-ray diffraction(XRD)methods,in terms of the surface morphology,phase composition,and element distribution of the alloy after 100 h corrosion.The results indicate that fineγ-particles with good cubic degree are uniformly distributed on the matrixγ'phase for the CH alloy.While theγ'-phase was deformed coarsened,and rafted,meanwhile spherical,needle like,and short rod like TCP phases did precipitated for the CH-LA alloy.The corrosion kinetics curves of the two different heat-treated alloys are similar to parabolas or segmented parabolas.The corrosion rate of CH alloy is relatively small,while a continuous Al_(2)O_(3) outer oxide scale is formed on the surface,and Al internal oxidation and Cr,Ni internal sulfidation occur in the inner layer,and slight spallation of the corrosion product scale was observed.The CH-LA alloy shows a relatively high corrosion rate with significant spallation of the formed surface corrosion products,which is a thick composite oxide scale with an extremely thin Al_(2)O_(3) scale on the surface,beneath that,there is a zone of internal oxidation of Al and internal sulfidation of Cr and Ni.

关 键 词：镍基单晶合金 长期时效 热腐蚀 TCP相 

分 类 号：TG178[金属学及工艺—金属表面处理]