原位生长Cr_3C_2-CrB复合增强镍基激光熔覆层研究  

Investigation on In-Situ Synthesis of Cr_3C_2-CrB Reinforced Ni-Based Composite Coatings by Laser Cladding

作　　者：敬晓定[1] 晁明举[1] 孙海勤[1] 张现虎[1] 梁二军[1] 

机构地区：[1]郑州大学物理工程学院材料物理教育部重点实验室,河南郑州450052

出　　处：《中国激光》2009年第1期231-237,共7页Chinese Journal of Lasers

基　　金：河南省教育厅自然科学研究计划(200510459005和2006140009)基金资助

摘　　要：采用预涂激光熔覆技术,在A3钢表面制备原位生长Cr3C2-CrB复合增强镍基激光熔覆层。使用金相显微镜、扫描电镜(SEM)、能谱仪(EDS)和X射线衍射(XRD)仪对熔覆层进行了显微组织和物相分析,并测试了熔覆层显微硬度及摩擦性能。结果表明,在适当工艺条件下,熔覆层成形良好、表面光滑,涂层与基体呈现良好的冶金结合。熔覆层底部组织为包含Cr,Fe的碳、硼化物的γ(NiFe)树枝晶结构。熔覆层中上部组织为先共晶析出、规则排列的Cr3C2杆状相和CrB颗粒相分布在Fe2C/γ(NiFe)共晶基体中。由于Cr3C2-CrB复合强化相的原位生成且均匀弥散分布在基体中,使得熔覆层具有高的硬度(平均硬度HV0.31100)和良好的耐磨性,其磨损失重仅为纯Ni60熔覆层的1/3。The Cr3C2 CrB reinforced Ni-based composite coating is successfully in situ synthesized by laser cladding on steel A3 substrate by prior pasting. The microstructural and rnetallographic analyses are performed by metallurgical microscope, scanning electron microscope （SEM）, energy-dispersive spectrometer （EDS）, and X ray diffractometer（XRD）. The microhardness and wear-resistance of the coatings are investigated. It is indicated that a smooth and in situ synthesized CraC2 CrB reinforced composite coating can be achieved employing a proper amount of （B2O3 ＋Cr2O3 ＋C） doping under suitable processing parameters, and the excellent bonding between the coating and substrate is ensured by the strong metallurgical interface. The bottom of the coating is composed of γ（NiFe） dendrite containing Cr,Fe borides and carbides. In the middle and upper zones of the coating, lots of pre-eutectic Cr3C2 rods are abreast arranged and CrB particles dispread in the Fe2C/γ（NiFe） eutectic matrix. Because of the presence of Cr3C2 - CrB reinforcements and their homogeneous distribution, the composite coating gives the high average hardness of HV0.3 1100 and better wear resistance. The wear mass loss of the composite coating is just one third of that of the pure Ni60 coating.

关 键 词：激光技术 激光熔覆 原位生成Cr3C2-CrB显微组织 耐磨性 

分 类 号：TN249[电子电信—物理电子学] TG665[金属学及工艺—金属切削加工及机床]