Fabrication of a nanocrystalline Ni-Co/CoO functionally graded layer with excellent electrochemical corrosion and tribological performance
Fabrication of a nanocrystalline Ni-Co/CoO functionally graded layer with excellent electrochemical corrosion and tribological performance
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DOI：
10.1088/0957-4484/17/18/014
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发表时间：
2006-09-28
期刊：
影响因子：
3.5
通讯作者：
Xue, Qunji
中科院分区：
文献类型：
--
作者：
Wang, Liping;Zhang, Junyan;Xue, Qunji
采用电沉积-循环热氧化-淬火工艺制备了具有优良润滑、高耐蚀、高耐磨性能的纳米晶Ni-Co/CoO功能梯度材料。透射电子显微镜和能量色散X射线能谱研究表明，随着存款厚度的增加，平均晶粒尺寸在13-40 nm范围内的块状Ni-Co梯度沉积物表现出从面心立方到六方密排的梯度结构转变，以及从富Ni区到富Co区的梯度成分变化。X射线衍射和X射线光电子能谱分析表明，NC Ni-Co梯度材料的表面层主要由（I 11）择优取向的致密超细CoO组成。与NC Ni和Ni-Co梯度镀层相比，NC Ni-Co/CoO功能梯度材料在NaOH和NaCl溶液中的耐腐蚀性显著提高，在干滑动磨损条件下的耐磨性和干自润滑性能显著改善。NC Ni-Co/CoO梯度材料具有较高的腐蚀和摩擦学性能，这主要归因于沉积层内部的梯度结构、致密氧化层的抗腐蚀屏障作用以及富CoO摩擦表面膜的固体润滑作用。
Nanocrystalline (NC) Ni-Co/CoO functionally graded materials with excellent lubricating, high anti-corrosion and anti-wear performance were fabricated by electrodeposition and subsequent cyclic thermal oxidation and quenching. Transmission electron microscopy and energy dispersive x-ray spectroscopy investigations show that bulk Ni-Co gradient deposits with an average grain size in the range of 13-40 nm demonstrated a graded structure transition from face-centred cubic to hexagonal close packed and graded composition changes from Ni-rich to Co-rich regions with the increase in deposit thickness. X-ray diffraction and x-ray photoelectron spectroscopy analysis indicated the surface layer of NC Ni-Co graded materials to be mainly composed of dense and ultrafine CoO with a (I 11) preferred orientation. The NC Ni-Co/CoO functionally graded materials exhibited significantly enhanced corrosion resistance in both NaOH and NaCl solutions and remarkably improved wear resistance and dry self-lubricating performance when compared with the NC Ni and Ni-Co graded deposits under dry sliding wear conditions. The higher corrosion and tribological performance of NC Ni-Co/CoO graded materials can be attributed to the graded microstructure within the deposits, the anti-corrosion barrier of a dense oxide layer and the solid lubrication effect of CoO-rich tribo-surface films.