Corrosion behaviors and mechanism of electroless Ni-Cu-P/n-TiN composite coating  

作　　者：ZHOU Hong-ming HU Xue-yi LI Jian 周宏明;胡雪仪;李荐(School of Materials Science and Engineering, Central South University;Hunan Province Zhengyuan Energy Storage Materials and Devices Research)

机构地区：[1]School of Materials Science and Engineering,Central South University,Changsha 410083,China [2]Hunan Province Zhengyuan Energy Storage Materials and Devices Research,Changsha 410083,China ~ Central South University Press and Springer-Verlag GmbH Germany,part of Springer Nature 2018

出　　处：《Journal of Central South University》2018年第6期1350-1357,共8页中南大学学报（英文版）

基　　金：Project(K1403375-11)supported by Science and Technology Planning Project of Changsha,China;Project(2015D009)supported by the Planned Science and Technology Project of Qingyuan City,China;Project(2015B04)supported by the Planned Science and Technology Project of Qingcheng District,Qingyuan City,China

摘　　要：In the present investigation, electroless Ni-Cu-P/n-TiN composite coating was prepared using alkaline citrate-based bath. X-ray diffraction （XRD）, scanning electron microscopy（SEM）, energy-dispersive spectroscopy（EDS）, electrochemical measurements, weight loss tests and Raman spectrometer were used to character the properties of the coating. As the Cu content increased from 7.3 wt% to 24.8 wt%, the corrosion current density of the Ni-Cu-P/n-TiN coating decreased from 10.80 to 4.34 ~tA. And the inclusion of Cu in NiP alloy resulted in refinement and less porosity in microstructure. The addition of TiN resulted in a slight decline in anti-corrosion property of the coating. As the mass loss test showed, Ni-24.8%Cu-P exhibited perfect corrosion resistance. Studies by Raman spectroscopy on coatings proved that Cu（II）3（PO4）（OH）3, Cu（OH）2 and CuO were examined while no compound of nickel was found, and Cu exhibited preferred corrosion in saline solution, providing cathodic protection to Ni alloy.本文以碱性柠檬酸为镀液,通过化学镀方法,制备了Ni–Cu–P/n–TiN复合镀层。分别采用XRD、SEM和EDS分析镀层的物相组成和组成形貌,采用电化学测试、失重试验、拉曼光谱仪来表征镀层的耐腐蚀性能。实验结果表明:Cu可细化Ni–Cu–P/n–TiN胞状组织并减少其结构中的孔隙率,当Cu含量在7.3 wt%~24.8 wt%时,复合镀层Ni–Cu–P/n–TiN的自腐蚀电流从10.80μA下降至4.34μA;而TiN的掺杂会使复合镀层Ni–Cu–P/n–TiN的耐腐蚀性能降低。失重试验表明,当Cu含量为24.8wt%时,镀层Ni–Cu–P的耐腐蚀性能较好。通过拉曼曲线分析可知,复合镀层中Cu表现出优先腐蚀机制,形成了Cu(Ⅱ)_3(PO_4)(OH)_3、Cu(OH)_2和CuO等Cu金属的腐蚀产物,为镍合金提供了很好的阴极保护作用。

关 键 词：Cu content TiN content corrosion resistance corrosion mechanism cathodic protection 

分 类 号：TG142.71[一般工业技术—材料科学与工程] TG174.442[金属学及工艺—金属材料]