40Cr钢表面激光熔覆Fe,Ni基涂层组织性能研究  

Microstructure and Properties of Laser Cladding Fe,Ni-Based Coatings on 40Cr Surface

作　　者：张敏[1] 王刚[1] 张立胜 许桓瑞 张云龙 许帅 Zhang Min;Wang Gang;Zhang Lisheng;Xu Huanrui;Zhang Yunlong;Xu Shuai(College of Material Science and Technology,Xi'an University of Technology,Xi'an 710048,China)

机构地区：[1]西安理工大学材料科学与工程学院,陕西西安710048

出　　处：《稀有金属》2021年第8期928-935,共8页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51974243);陕西省自然科学基础研究计划(2019JZ-31);西安市科技计划项目(201805037YD15CG21(16))资助。

摘　　要：为了提高40Cr钢基体的力学性能和耐蚀性,利用激光熔覆方法在40Cr钢基体上熔覆Fe基、Ni基合金涂层。通过扫描电子显微镜(SEM)、能谱分析仪(EDS)、X射线衍射仪(XRD)对涂层的组织、相以及元素分布进行分析鉴定,并采用显微硬度、电化学腐蚀及摩擦磨损测试手段表征了两种涂层的综合性能。结果表明:两种涂层的厚度均为4 mm左右,且涂层与基体结合界面处均有明显过渡带,形成了较好的冶金结合。其中Fe基涂层显微组织主要由α-Fe和FeCr相组成,而Ni基涂层显微组织主要由γ-Ni和FeNi3相组成;Fe基、Ni基涂层的显微硬度值分别为HV_(0.5)440和HV_(0.5)340,均高于基体(HV_(0.5)240)。此外,Fe基、Ni基涂层相对基体而言均具有较低的腐蚀电流密度(0.51,1.08μA·cm^(-2))和较高的自腐蚀电位(-0.26 V),同时Fe基和Ni基涂层较基体的相对耐磨性分别提高了11.2倍和2倍,两种涂层均改善了40Cr钢基体的耐腐蚀性和耐磨性,其中Fe基涂层的耐腐蚀性和耐磨性能较优。40 Cr steel was suitable for application in mining machinery,automotive semi-shaft and other construction machinery fields,due to its good toughness and hardenability,high fatigue strength,good machinability and other characteristics,However,it failed due to the inevitable wear and corrosion in the working conditions,causing huge economic losses,and this result could be improved by surface engineering technology. Advanced surface engineering technology could improve the surface properties of materials by selecting reasonable coatings,which was of great significance for improving the service life of materials and reducing costs. In order to improve the mechanical properties and corrosion resistance of 40 Cr steel substrate surface,Fe-and Ni-based alloy coatings were fused on 40 Cr steel substrate by laser cladding. Firstly,the wire cutting equipment was used to prepare specimens of different sizes,for the specimens that needed to be observed(except X-ray diffractometer(XRD)specimens). Then the samples were mechanically polished and corroded with a mixed solution of 1 ml HF+2 ml HNO_(3)+2 ml C3H8O_(3)+8 ml H_(2) O. The microstructure,phase and element distribution of the coating were characterized by scanning electron microscope(SEM),energy disperse spectrum analyzer(EDS)and XRD. The mechanical properties of the two coatings at room temperature were characterized by microhardness and friction and wear testing methods. At the same time,the corrosion resistance of them was determined by studying their electrochemical activity in the3.5%NaCl solution system. The results showed that the thickness of the two coatings was about 4 mm,the dendrite morphology of the coating under the metallographic phase conformed to the growth law of the dendrites of the typical solidification theory. From the bonding interface to the middle region of the coating,the dendrite morphology was plane crystal,cellular crystal and columnar crystal in turn. The surface region of the coating presents finer dendrite morphology,which was caused by t

关 键 词：激光熔覆 Fe基合金涂层 NI基合金涂层 电化学腐蚀 摩擦磨损 

分 类 号：TG174.4[金属学及工艺—金属表面处理]