Pt改性梯度NiCrAlY涂层的热腐蚀行为研究  

Hot Corrosion Behavior of Pt Modified Gradient NiCrAlY Coatings

作　　者：孙日 王铁钢[1] 李伟[2] 尹霜 刘艳梅[1] 姜肃猛[2] SUN Ri;WANG Tiegang;LI Wei;YIN Shuang;LIU Yanmei;JIANG Sumeng(Tianjin Key Laboratory of High Speed Cutting and Precision Manufacturing,Tianjin University of Technology and Education,Tianjin 300222,China;Division of Surface Engineering of Materials,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)

机构地区：[1]天津职业技术师范大学天津市高速切削与精密加工重点实验室,天津300222 [2]中国科学院金属研究所材料表面工程研究部,辽宁沈阳110016

出　　处：《材料保护》2024年第3期28-37,49,共11页Materials Protection

基　　金：辽宁省博士科研启动基金计划项目(2022-BS-004);天津市多元投入基金重点项目(22JCZDJC00670)资助。

摘　　要：为了进一步提高NiCrAlY涂层的抗热腐蚀性能,利用电弧离子镀技术在DZ125合金表面分别沉积NiCrAlY/NiAl/Al涂层(coating A)、NiCrAlY/Pt/NiAl/Al涂层(coating B),再经真空扩散退火处理形成成分渐变的梯度涂层结构。在涂层中引入改性元素Pt以改善涂层的抗热腐蚀能力,对比研究了2种涂层体系在900℃不同混合盐中的热腐蚀行为;利用SEM、EDS、XRD以及EPMA分析了涂层经过热腐蚀后的微观形貌、物相组成和元素分布。结果表明:在900℃的K_(2)SO_(4)+Na_(2)SO_(4)混合盐中,coating A表面的氧化膜发生了大面积的剥落,coating B中的Pt抑制了S在涂层/氧化膜界面处的偏析,增强了氧化膜的黏附性。在900℃的NaCl+Na_(2)SO_(4)混合盐中,coating A的Cr元素和O元素分别发生了外扩散和内扩散,Cr外扩散易与S反应生成有害相Cr_(x)S_(y)。coating B中的Pt抑制了Cr、O元素的外扩散和内扩散。在NiCrAlY层和NiAl层之间增加Pt层,显著提升了NiCrAlY涂层在混合盐中的抗热腐蚀能力。For further enhancing the hot corrosion resistance of the NiCrAlY coating,the NiCrAlY/NiAl/Al coating(coating A)and the NiCrAlY/Pt/NiAl/Al coating(coating B)were deposited on the surface of DZ125 alloy by arc ion plating technology,and then the gradient coating structure with gradually changing composition was formed by vacuum diffusion annealing.The modified element Pt was introduced into the coating to enhance the hot corrosion resistance of the coating,and the hot corrosion behavior of two coating systems in different mixed salts at 900℃was studied.Additionally,the microstructure,phase composition and element distribution of the coating after hot corrosion were ana-lyzed by SEM,EDS,XRD and EPMA.Results showed in a mixed salt of K_(2)SO_(4)+Na_(2)SO_(4) at 900℃,the extensive spalling of the oxide film occurred on the surface of coating A.Pt in coating B inhibited the segregation of S at the coating/oxide film interface,and enhanced the adhe-sion of the oxide film.In the mixed salt of NaCl+Na_(2)SO_(4) at 900℃,the Cr element and O element of coating A underwent outward diffusion and inward diffusion,respectively.The outward diffusion of Cr was easy to react with S to form a harmful phase Cr_(x) S_(y).In contrast,the Pt in coating B inhibited the outward diffusion and inward diffusion of Cr and O elements.Overall,the addition of Pt layer between NiCrAlY and NiAl layers significantly enhanced the hot corrosion resistance of the NiCrAlY coating in mixed salts.

关 键 词：电弧离子镀 梯度NiCrAlY涂层 α-Cr Pt改性 热腐蚀 

分 类 号：TG174.44[金属学及工艺—金属表面处理]