脉冲电沉积纳米晶Ni-Co合金镀层腐蚀特性研究

Corrosion Characteristic of Pulsed Electrodeposition Nanocrystalline Ni-Co Alloy Coating

摘要:

采用X射线衍射(XRD)、扫描电镜(SEM)、能谱分析(EDS)等方法研究了脉冲电沉积法制备纳米晶Ni和纳米晶Ni-Co合金镀层的组织结构、表面形貌和成分。用浸泡法和电化学极化法研究了纳米晶Ni和不同Co含量的纳米晶Ni-Co合金镀层在3.5% NaCl (质量分数，下同)和5% HCl溶液中的腐蚀行为。结果表明： 通过脉冲电沉积法制备的Ni和Ni-Co合金镀层具有典型的纳米晶结构；随着含Co量的增加，镀层的晶粒尺寸减小，硬度增加；所制备的纳米晶Ni-Co合金镀层组织结构均匀致密，其在3.5% NaCl溶

Abstract:

The microstructures, the surface morphology and the composition of nanocrystalline Ni and nanocrystalline Ni-Co alloy prepared by pulse electrodeposition have been studied by XRD, SEM and EDS. The corrosion behaviors of nanocrystalline nickel and Ni-Co alloys in the solutions containing 305% (mass fraction) NaCl and 5% (mass fraction) were investigated by soak method and electrochemical polarization method respectively. The experimental results indicate that typical nanocrystalline nickel and Ni-Co alloy coatings can be synthesized by pulse electrodeposition, and the alloying element Co had an effect of solution strengthening and grain size refinement. The nanocrystalline Ni-Co alloy is dense in nature and it exhibited better corrosion resistance in 3.5% (mass fraction) NaCl solution and 5% (mass fraction) HCl solution than the nanocrystalline nickel. The surface morphology of all samples after corrosion in 3.5% (mass fraction) NaCl solution show good corrosion resistance, however, the samples were uniformly corroded in 5% (mass fraction) HCl solution.