电火花沉积FeCoCrNiCu高熵合金涂层的组织结构与耐蚀性  

Microstructure and Corrosion Resistance of FeCoCrNiCu High-entropy Alloy Coating Prepared by Electro-spark Deposition

作　　者：王彦芳 闫晗 李娟 孙胜越 宋增金 石志强 WANG Yan-fang;YAN Han;LI Juan;SUN Sheng-yue;SONG Zeng-jin;SHI Zhi-qiang(School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China)

机构地区：[1]中国石油大学(华东)材料科学与工程学院

出　　处：《表面技术》2019年第6期144-149,共6页Surface Technology

基　　金：山东省自然科学基金(ZR2019MEM032);广西大学广西有色金属及特色材料加工重点实验室开放基金(GXKFJ16-09)~~

摘　　要：目的通过在45Mn2钢表面进行电火花沉积Fe CoCrNiCu高熵合金涂层,改变其表面性能。方法采用真空吸铸法制备直径为3mm的Fe CoCrNiCu高熵合金电极,采用电火花沉积技术,在45Mn2钢表面制备高熵合金沉积层。通过X射线衍射仪(XRD)、光学显微镜(OM)、扫描电子显微镜(SEM)等分析研究沉积层的相组成、表面形貌、表面粗糙度和显微组织。通过三电极体系对涂层进行极化曲线和电化学阻抗谱(EIS)测试,分析其在3.5%NaCl溶液中的电化学腐蚀行为。结果制备的Fe CoCrNiCu涂层连续、均匀,具有简单的FCC结构,表面呈银灰色橘皮状,厚度约为25μm。涂层表面凸凹不平,为典型的“溅射状”花样形貌,表面粗糙度均方根偏差Rq约为4μm。极化曲线表明,高熵沉积层自腐蚀电位为-0.548 V,较45Mn2基材正移约180m V,腐蚀电流密度为1.59μA/cm^2,约为基材的1/6。电化学阻抗谱EIS测试结果显示,Fe CoCrNiCu高熵合金沉积层较45Mn2基材具有更大的容抗弧半径和极化电阻,其模拟电路可以用R(Q(R(QR)))表示。结论电火花沉积技术是一种极具发展潜力的高熵合金涂层制备技术,制备的Fe CoCrNiCu高熵合金涂层可有效提高基材的耐蚀性能。The work aims to deposit FeCoCrNiCu high-entropy alloy coating on 45Mn2 steel to improve the surface properties. FeCoCrNiCu high-entropy alloy rod with a dimeter of 3 mm was prepared by copper mold suction casting and the FeCo- CrNiCu high-entropy alloy coating was deposited on 45Mn2 steel surface by electro-spark deposition technique. The phase composition, surface morphologies and microstructures of the deposited coatings were analyzed by optical microscope (OM), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The electrochemical corrosion behaviors of the deposited coating in 3.5%NaCl were measured by polarization curves and electrochemical impedance spectroscopy. The prepared FeCoCrNiCu coating was continuous and uniform with a simple FCC structure. The surface was silver-gray orange peel and about 25 μm thick. The surface of the coating was uneven and showed typical "sputtering" pattern. The root mean square deviation (Rq) of the surface roughness was about 4 μm. The polarization curves showed that the self-corrosion potential of the high-entropy deposits was -0.548 V, which was 180 mV higher than that of 45Mn2 substrates, and the corrosion current density was 1.59 μA/cm^2, which was about 1/6 of that of the substrates. The EIS results of electrochemical impedance spectroscopy showed that the FeCoCrNiCu high-entropy alloy deposit had larger capacitive arc radius and polarization resistance than 45Mn2 substrate, and the analog circuit could be expressed by R(Q(R(QR)). Electro-spark deposition (ESD) is a promising technology for preparing high-entropy alloy coatings. The high-entropy FeCoCrNiCu coating prepared can effectively improve the corrosion resistance of the substrate.

关 键 词：电火花沉积 高熵合金 涂层 组织 电化学 

分 类 号：TG174.4[金属学及工艺—金属表面处理]