铜材表面激光合金化和激光熔覆制备Ni/Cu-Cr_3C_2/Co梯度涂层  

Preparation of Ni/Cu-Cr_3C_2/Co Gradient Coating in the Combination of Laser Alloying and Laser Cladding Technologies on Copper Products

作　　者：赵健[1] 刘光[1] 马冰[1] 郑子云[1] 历天翼 戴宇[1] ZHAO Jian;LIU Guang;MA Bing;ZHENG Zi-yun;LI Tian-yi;DAI Yu(Ningbo Branch,China Academy of Ordnance Science,Ningbo 315103,China;Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences,Ningbo 315201,China)

机构地区：[1]中国兵器科学研究院宁波分院,浙江宁波315103 [2]中国科学院宁波材料技术与工程研究所,浙江宁波315201

出　　处：《表面技术》2018年第8期162-169,共8页Surface Technology

基　　金：宁波市科技创新团队项目(2014B82001)~~

摘　　要：目的提高铜合金的表面硬度,改善其耐磨性能。方法利用激光表面合金化和激光熔覆工艺在铜合金表面制备出Ni/Cu-Cr_3C_2/Co梯度涂层。采用X射线衍射仪、扫描电镜及能谱仪,系统分析了合金化过渡层与熔覆层的物相构成及显微组织,通过硬度测试、摩擦磨损实验,对梯度涂层的显微硬度和耐磨性进行评估。结果合金化过渡层组织致密且具有单一柱状晶结构,主要由α-(Cu,Ni)固溶体、Ni_3Al和Ni Al构成。Cr_3C_2/Co复合熔覆层中分布着未熔Cr_3C_2颗粒,且以未熔Cr_3C_2颗粒为中心,四周有大量呈杆状(或针状)的M_(23)C_6和M_7C_3型碳化物,这种碳化物可以有效提高熔覆层的硬度。梯度涂层的显微硬度从基体的80HV逐渐增加到熔覆层的640HV,梯度涂层的摩擦磨损失重仅为铜合金基体的1/8。铜基体的磨损表面发生大规模破坏并形成大量磨屑,其磨损机制主要是粘着磨损;Cr_3C_2/Co喷涂层由于内部结合力较弱,出现了大量的疲劳磨损面,其磨损机制为表面疲劳磨损;而Ni/Cu-Cr_3C_2/Co梯度涂层的磨损表面比较平整,只存在轻微的"犁沟",其磨损机制为典型的磨粒磨损。结论梯度涂层由于Cr_3C_2、M_(23)C_6及M_7C_3相的存在,显微硬度和耐磨性能显著提高。同时,涂层的成分与性能均呈一定的梯度变化,改善了铜基体与涂层的相容性。The work aims to improve surface hardness and wear resistance of copper alloys.A Ni/Cu-Cr3C2/Co gradient coating was prepared successfully on the surface of copper alloy by combining laser alloying and laser cladding technologies.Phase composition and microstructure of the gradient coating were analyzed by X-ray diffractometer,scanning electron microscope,energy dispersive spectrometer,etc.Microhardness and wear resistance of the gradient coating were evaluated by hardness test and friction-wear test.The alloying transition layer was dense and had a single columnar crystal structure,and phases were mainly composed ofα-(Cu,Ni),Ni3Al and NiAl.Undissolved Cr3C2 particles were distributed in the Cr3C2/Co composite cladding layers.A large number of rod-like(or needle-like)M23C6 and M7C3 carbides centered around the undissolved Cr3C2 particles,which could effectively improve hardness of the cladding layer.Microhardness of the gradient coating gradually increased from the 80HV(substrate)to 640HV(cladding layer),and friction-wear loss of the gradient coating was only 1/8 of copper substrate.There was much debris on the worn surface of copper substrate due to massive destruction,and its wear mechanism was mainly adhesive wear.Due to weak internal bonding force,a large number of fatigue wear surfaces appeared on the Cr3C2/Co sprayed coating,and the wear mechanism was surface fatigue wear.However,worn surface of the Ni/Cu-Cr3C2/Co gradient coating was relatively smooth,there were some slight"furrows",and its wear mechanism was typical abrasive wear.Because of the existence of Cr3C2,M23C6 and M7C3 phases,microhardness and wear resistance of the gradient coating are significantly improved.Meanwhile,composition and properties of the coating show a certain gradient change,which improves the compatibility between copper substrate and coating.

关 键 词：铜合金 激光表面合金化 激光熔覆 梯度涂层 显微硬度 磨损机制 

分 类 号：TG166.2[金属学及工艺—热处理] TH117[金属学及工艺—金属学]