激光熔覆碳纳米管增强高熵合金涂层及耐腐蚀性能  

Laser Cladding High-Entropy Alloy Coating Reinforced by Carbon Nanotubes and Its Corrosion Resistance

作　　者：韩冰 陈曦[3] 姜梦[3] 陈文龙 张东东 曹立超 张俊爽 滕宪斌 陈彦宾[3] Han Bing;Chen Xi;Jiang Meng;Chen Wenlong;Zhang Dongdong;Cao Lichao;Zhang Junshuang;Teng Xianbin;Chen Yanbin(School of Marine Engineering,Guangzhou Maritime University,Guangzhou 510725,Guangdong,China;Institute of Intelligent Manufacturing,Guangdong Academy of Science,Guangzhou 510070,Guangdong,China;State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,Harbin 150001,Heilongjiang,China;Center for Industrial Analysis and Testing,Guangdong Academy of Science,Guangzhou 510650,Guangdong,China;School of Vanadium and Titanium,Panzhihua University,Panzhihua 617000,Sichuan,China)

机构地区：[1]广州航海学院轮机工程学院,广东广州510725 [2]广东省科学院智能制造研究所,广东广州510070 [3]哈尔滨工业大学先进焊接与连接国家重点实验室,黑龙江哈尔滨150001 [4]广东省科学院工业分析检测中心,广东广州510650 [5]攀枝花学院钒钛学院,四川攀枝花617000

出　　处：《中国激光》2023年第24期98-106,共9页Chinese Journal of Lasers

基　　金：国家自然科学基金(52105326);广州市基础与应用基础研究项目(202102020725);广东省科学院“千名博士(后)计划”引进专项(2020GDASYL-20200103125)。

摘　　要：通过机械混合方法解决了碳纳米管(CNTs)在Co Cr Fe Ni高熵合金粉体表面的团聚问题,采用激光熔覆方法在304不锈钢基板上制备了Co Cr Fe Ni-CNTs涂层,碳纳米管优化质量分数为1.0%,研究了涂层微观组织、显微硬度及抗中性盐雾腐蚀性能。结果表明:涂层的晶粒为单一的面心立方(FCC)结构,按照晶粒形态可以分为平面晶、胞状枝晶、柱状枝晶、等轴晶,晶界上形成了M_(7)C_(3)型碳化物共晶相,未分解碳纳米管弥散分布在晶粒内,Si/C类夹杂物来自于熔化的基板材料。涂层内硬度分布较均匀,由于碳纳米管和M_(7)C_(3)碳化物的第二相强化作用,硬度水平可以比Co Cr Fe Ni涂层提高70 HV以上。经中性盐雾腐蚀269 h后,点蚀仅发生在脱落的Si/C类夹杂物周围区域,而在晶粒及晶界内其他区域均未发现腐蚀现象,因此,严格限制Si/C类夹杂物进入涂层将进一步改善复合涂层的抗中性盐雾腐蚀性能。Objective The research of laser cladding CoCrFeNi high-entropy coating reinforced by carbon nanotubes(CNTs)is still limited.The corrosion resistance of a new CoCrFeNi-CNTs composite coating is highly necessary.However,solving the agglomeration problem of CNTs on raw powder surface is quite challenging and key in the laser cladding process of CoCrFeNi-CNTs composite coating.The microstructure and neutral salt spray corrosion resistance are highly important characteristics for studying laser cladding CoCrFeNi-CNTs composite coating.Methods CoCrFeNi and multi-walled CNTs raw powders are mixed by mechanical mixing method without milling ball.The optimized mixing parameters are CNT mass fraction of 1.0%,rotation speed of 240 r/min,mixing time of 10 h,drying time of 4 h,and argon gas protection.The CoCrFeNi-CNTs composite coating is fabricated on a 304 stainless steel substrate using a system platform consisting of a 6-axis industrial robot,a fiber laser,a powder feeder,and an alternating strategy with 90°rotation for each layer.The optimized laser cladding parameters are laser power of 870 W,laser scanning velocity of 12.5 mm/s,overlap rate of 50%,powder feeding rate of 8.7 g/min,layer thickness of 0.5 mm,and argon gas flow rate of 20 L/min.The macrostructural characteristics of the CoCrFeNi-CNTs composite coating is observed using an optical microscope(OM).The precipitated phases are detected using an X-ray diffraction(XRD).The microstructural features of the CoCrFeNi-CNTs composite powder and CoCrFeNiCNTs composite coating are analyzed using a scanning electron microscope(SEM).The elemental distributions of grain,intergranular carbide eutectics,and inclusion in the CoCrFeNi-CNTs composite coating are investigated using an energy dispersive spectrometry(EDS).The distribution of CNTs in the CoCrFeNi-CNTs composite coating is further observed using a transmission electron microscope(TEM).The microhardness distribution from top to fusion line in the CoCrFeNi-CNTs composite coating is tested using a digital microhardnes

关 键 词：激光技术 高熵合金 硬度 中性盐雾腐蚀 

分 类 号：TG146.4[一般工业技术—材料科学与工程]