激光熔覆Cu-Mn合金电解腐蚀选择性溶解及纳米多孔涂层制备研究

来源期刊：金属学报2011年第3期

论文作者：谷雨 董长胜 马明星 钟敏霖 刘文今

文章页码：349 - 353

关键词：激光熔覆； Cu-Mn合金； 脱合金； 纳米多孔

Key words：laser cladding； Cu-Mn alloy； dealloying； nanoporous

摘    要：采用激光熔覆结合熔覆层激光快速重熔工艺,在45钢表面制备了成形良好、稀释率低的Cu-Mn合金涂层,涂层微观组织为细小的树枝晶,随着激光重熔速度的提高,二次枝晶间距统计平均值从3.1μm减小为1.6μm.动电位扫描测试表明,对于不同的电解液,Cu-Mn合金表现出选择性溶解特性.对合金涂层在HCl和KNO₃溶液中进行电解腐蚀脱合金后,分别成功制备了纳米多孔结构的Cu涂层和Mn涂层.纳米多孔Cu孔径尺寸为30-50 nm,而纳米多孔Mn的微观形貌为类似于"丝瓜筋"的网状结构,粗糙度系数高达900.

Abstract: Nanoporous metals have attracted considerable attention for a wide range of applications in catalysis,sensing and bio-detection due to their large surface-to-volume ratios and excellent thermal and electrical conductivities.It has been proven that dealloying is the most effective method to yield nanoporous metals.Recently,a number of nanoporous metals,including Au,Ag and Pt have been synthesized by dealloying.Most of the research focused on etching the more active components from the precursors in different electrolyte owing to their higher reactivity,such as Ag,Al,Zr and Mn.In this paper selective dissolution of Cu or Mn components from Cu-Mn alloys was reported, and nanoporous coatings were fabricated by a two-step process involving high power laser cladding of a homogeneous Cu40Mn60 alloy coatings followed by selectively electrochemical dealloying.Cu-Mn alloy coatings with fine shape,low dilute ratio and refined microstructure were fabricated on mild steel by means of laser processing.The second dendrite arm spacing (SDAS) decreased with the increasing of laser remelting speed.The SDAS can be refined to be 1.6μm with the laser remelting speed 83 mm/s.Polarization curve indicates that Cu-Mn alloy shows selective dissolution characteristics for different electrolytes.Nanoporous Cu and nanoporous Mn were fabricated with optimal electrochemically dealloying parameters in 0.1 mol/L HCl and 0.1 mol/L KNO₃ solution respectively.Nanoporous Cu with pore size ranges from 30 nm to 50 nm,while the surface morphology of the porous Mn was a ribbon-like structure with ultrahigh roughness factor up to 900.