Mo含量对镍基合金熔覆层高温腐蚀特性的影响  

Effect of Mo content on high-temperature corrosion resistance of Ni-based alloy cladding layer

作　　者：彭波 王智春[1] 张瑜彤 李悦 韩哲文[1] 张鹏鲲 PENG Bo;WANG Zhichun;ZHANG Yutong;LI Yue;HAN Zhewen;ZHANG Pengkun(North China Electric Power Research Institute Co.,Ltd.,Beijing 100045,China;North China Electric Power University,School of Energy,Power and Mechanical Engineering,Beijing 102206,China)

机构地区：[1]华北电力科学研究院有限责任公司,北京100045 [2]华北电力大学能源动力与机械工程学院,北京102206

出　　处：《材料科学与工艺》2025年第1期64-71,共8页Materials Science and Technology

基　　金：华北电力科学研究院有限责任公司科技项目(KJZ2023011)。

摘　　要：本文研究了Mo含量分别为0wt.%、5wt.%、10wt.%的3种Ni-22Cr-xMo镍基合金熔覆层的高温腐蚀行为,探讨其用于生物质电厂受热面管高温腐蚀防护的理论可行性。以KCl和NaCl混合盐为腐蚀介质模拟生物质电厂焚烧环境,测量了在650℃、168 h后3种熔覆层试样的高温腐蚀累积失重量,利用SEM、EDS、XRD分别对腐蚀产物的微观形貌、元素成分及物相组成进行了测试分析。结果表明:无Mo熔覆层的氧化皮最厚,且与熔覆层之间存在较大的裂隙;添加Mo元素后,氧化皮与熔覆层之间未见明显裂隙,氧化皮厚度减小,表面Cr元素的质量分数有所提高,内部出现了明显的贫铬区,且贫铬区富集了大量的Mo,阻止了腐蚀的进一步内侵。但Mo的含量并不是越多越好,添加10wt.%Mo时,Mo元素在熔覆层内部分布的连续性比添加5wt.%Mo时相对较差,不利于阻止腐蚀向内部延伸;添加10wt.%Mo熔覆层的氧化皮比无Mo熔覆层更薄,但累积失重量却更大,说明添加过多的Mo会生成大量的挥发性产物,反而降低熔覆层的耐腐蚀性能。添加5wt.%Mo元素的Ni-22Cr-xMo镍基合金熔覆层氧化皮与熔覆层之间结合性良好,表现出较高的耐高温腐蚀特性,对基体的保护作用更好。The high-temperature corrosion behaviors of three Ni-22Cr-xMo nickel alloy cladding layers with Mo content of 0wt.%,5wt.%and 10wt.%were investigated to explore the theoretical feasibility of using it for high-temperature corrosion protection of heating tube in biomass power plants.The mixed salt of KCl and NaCl was used as the corrosive medium to simulate the biomass power plants incineration environment.The cumulative weight loss of the three samples after high temperature corrosion at 650℃for 168 h was measured.The microscopic morphology,elemental composition and phase composition of the corrosion products were detected and analyzed by using Scanning Electron Microscope with Energy Dispersive Spectrometer(SEM/EDS)and X-ray Diffraction(XRD).The results show that the oxide scale of the cladding layer without Mo addition is the thickest,and there is large crack between it and the cladding layer.After the addition of Mo element,there is no obvious crack between the oxide scale and the cladding layer.The thickness of the oxide scale decreases,the mass fraction of Cr on the surface increases,and the chromium-poor area appears internally,and a large amount of Mo is enriched in the chromium-poor area,which prevents the further internal invasion of corrosion.However,the content of Mo is not as much as possible.When 10wt.%Mo is added,the continuity of Mo element distribution inside the cladding layer is relatively poor compared to adding 5wt.%Mo,which hinders the prevention of corrosion from extending inward.The oxide scale of cladding layer containing 10wt.%Mo is thinner than that of without Mo addition,but the cumulative weight loss is larger,indicating that excessive Mo additionl generates a large amount of volatile products,which reduces the corrosion resistance of the cladding layer.The Ni-22Cr-xMo Ni-based alloy cladding layer with 5wt.%Mo addition has good bonding between the oxide scale and the cladding layer,exhibiting higher high-temperature corrosion resistance and providing better protection of the matrix.

关 键 词：激光熔覆 镍基合金 高温腐蚀 Mo含量 生物质焚烧环境 

分 类 号：TG174[金属学及工艺—金属表面处理]