激光熔覆Mo_(2)NiB_(2)-Cr_(7)C_(3)复合陶瓷熔覆层组织结构与性能研究  

Investigation on the Microstructure and Properties of the Laser Cladded Mo_(2)NiB_(2)-Cr_(7)C_(3) Composite Coatings

作　　者：倪晓杰 张博文 赵忠贤 王生泽[1] 顾昊文 胡肇炜[2] 李文戈[2] NI Xiao-jie;ZHANG Bo-wen;ZHAO Zhong-xian;WANG Sheng-ze;GU Hao-wen;HU Zhao-wei;LI Wen-ge(School of Mechanical Engineering,Donghua University,Shanghai 201620,China;Merchant Marine College,Shanghai Maritime University,Shanghai 201306,China)

机构地区：[1]东华大学机械学院,上海201620 [2]上海海事大学商船学院,上海201306

出　　处：《表面技术》2021年第5期60-69,共10页Surface Technology

基　　金：国家自然科学基金项目(52002242,52072236)。

摘　　要：目的采用激光熔覆法在45#钢表面制备耐磨耐蚀的Mo_(2)NiB_(2)-Cr_(7)C_(3)复合陶瓷熔覆层,并研究制备工艺对组织结构与性能的影响。方法采用3 mm/s与4 mm/s的激光扫描速率及添加Cr_(7)C_(3)颗粒的工艺,激光熔覆制备Mo_(2)NiB_(2)-Cr_(7)C_(3)熔覆层。利用扫描电镜、X射线能谱仪、X射线衍射仪对熔覆层的组织结构、元素分布与物相组成进行分析。利用维氏显微硬度计、摩擦磨损仪与电化学工作站对熔覆层的硬度、摩擦性能与腐蚀性能进行分析。结果 Mo_(2)NiB_(2)-Cr_(7)C_(3)复合陶瓷熔覆层与45#钢基材间存在熔合过渡区,形成良好的冶金结合。熔覆层物相主要由Mo_(2)NiB_(2)、Cr_(7)C_(3)、{Fe Ni}合金相组成,其中Mo_(2)NiB_(2)相与Cr_(7)C_(3)相在熔覆层中间位置处聚集,3 mm/s扫描速率增加了{Fe Ni}相的含量。熔覆层的显微硬度由表及里先增后减,最高值可达1300HV_(0.1)以上,可提高45#钢的硬度(220HV_(0.1))6倍。相较于45#钢,熔覆层具有更低的摩擦因数、磨损量与更优的耐腐蚀性能,其中4 mm/s制备的Mo_(2)Ni B_(2)-Cr_(7)C_(3)硬度最高,耐磨性能最优(平均摩擦因数为0.66,磨痕深度为8.6μm),耐腐蚀性能最好(腐蚀电流比45#钢低1个数量级)。结论较高的扫描速率(4 mm/s)与Cr_(7)C_(3)颗粒的添加可有效提高Mo_(2)NiB_(2)-Cr_(7)C_(3)熔覆层的机械与耐腐蚀性能,可用于45#钢的表面改性。A wear-resistant and corrosion-resistant Mo2NiB2-Cr7C3 composite coatings were prepared on the substrate of 45#steel by laser cladding.The effects of laser cladding parameters including scanning rates of 3 and 4 mm/s and the addition of Cr7C3 particles on the microstructure and properties of the cladding coatings were investigated.The SEM,EDS,XRD,micro-hardness tester,friction and wear tester and electrochemical workstation were used to character the microstructure,composition and properties of the cladding coatings.Results showed that a fusion transition zone was appeared between the cladding coating and the substrate,consequently leading to a good metallurgical bond.The main phases in cladding coating were Mo2NiB2,Cr7C3 and{FeNi}phases.The Mo2NiB2 and Cr7C3 phases preferred gathering in the middle of the cladding coatings.And the laser scan rate of 3 mm/s brought in the increased content of{FeNi}phase in the coating.From top layer to bottom layer of the coating,the micro-hardness firstly increased and then decreased,in which the highest micro-hardness could reach more than 1300HV0.1,6 times higher than that of 45#steel(220HV0.1).Compared with 45#steel,the cladding coatings possessed the lower friction coefficient and wear loss and better corrosion resistance.Especially,the Mo2NiB2-Cr7C3 coating prepared at 4 mm/s possessed the highest micro-hardness,the best wear resistance(friction coefficient of 0.66,scratch depth of 8.6μm)and the best corrosion resistance(Jcorr is one order of magnitude lower than 45#steel).Therefore,the high laser scanning rate(4 mm/s)and the addition of Cr7C3 particles could effectively enhance the mechanical properties and corrosion resistance of the Mo2NiB2-Cr7C3 coatings,consequently fulfilled the surface modification of 45#steel.

关 键 词：激光熔覆 Mo_(2)NiB_(2) 激光工艺 组织结构 性能 

分 类 号：TG174.4[金属学及工艺—金属表面处理] V261.8[金属学及工艺—金属学]