| 硫酸盐体系三价铬沉积机理及镀层表征 |
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| 引用本文： | 闫慧,黄帅帅,杨防祖,田中群,周绍民. 硫酸盐体系三价铬沉积机理及镀层表征[J]. 电化学, 2018, 24(1): 20. DOI: 10.13208/j.electrochem.170441 |
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| 作者姓名： | 闫慧 黄帅帅 杨防祖 田中群 周绍民 |
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| 作者单位： | 厦门大学化学化工学院, 固体表面物理化学国家重点实验室, 福建厦门 361005 |
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| 基金项目： | 国家自然科学基金项目（No. 21621091）资助 |
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| 摘 要： | 在新研发的硫酸盐三价铬镀厚铬的镀液体系中, 运用线性扫描伏安法(LSV)和循环伏安法(CV)对三价铬在铜电极表面的电沉积过程进行研究, 并运用X射线荧光测厚仪、扫描电子显微镜(SEM)、X射线能量色散谱(EDS)、X射线衍射仪(XRD)、显微硬度计和Tafel曲线表征铬镀层厚度、形貌、组成、结构、显微硬度及在3.5wt% NaCl溶液中的耐蚀性. 结果表明, 在该体系中三价铬的沉积过程分两步进行(Cr3+ + e →Cr2+ , Cr2+ + 2e → Cr), 第一步得到1个电子, 受电化学过程和扩散过程共同控制, 第二步得到2个电子, 为扩散控制下的不可逆过程; 该镀层为瘤状纳米晶结构, 镀层中含有少量的铁元素(1.10 wt%), 显微硬度达到789.2 Hv, 镀层在3.5wt% NaCl溶液中的腐蚀电位(Ecorr)为-0.29 V, 腐蚀电流密度(jcorr)为9.26×10-5 A·dm-2.
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| 关 键 词： | 三价铬 硫酸盐 厚铬 电沉积 机理 镀层表征. |
| 收稿时间： | 2017-04-14 |
Deposition Mechanism and Coating Characterization for the Trivalent Chromium Electrodeposition in Sulphate Electrolyte |
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| Abstract: | Linear sweep voltammetry (LSV) and cyclic voltammetry (CV) were used to study the electrodeposition mechanism of trivalent chromium on a copper electrode in the novel sulphate electrolyte for thick trivalent chromium plating. The thickness, morphology, composition, microhardness, and structure, as well as the corrosion resistance in 3.5wt% NaCl solution of the trivalent chromium coatings were investigated by X-ray fluorescence gage, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), microhardness tester, X-ray diffraction (XRD) and Tafel curve measurements. The results showed that the electrodeposition of trivalent chromium involved two consecutive one electron reduction steps. The first step,Cr3+ + e →Cr2+,is controlled by the electrochemical reduction and diffusion processes, and the second step,Cr2+ + 2e → Cr, is an irreversible process under the diffusion control. The trivalent chromium coating exhibited nodular nanocrystalline structure and contained a small amount of iron (1.10wt%). The microhardness of the coating reached to 789.2 Hv. The corrosion potential (Ecorr) and corrosion current density (jcorr) of the coating in 3.5wt% NaCl solution were determined to be -0.29 V and 9.26×10-5 A·dm-2, respectively. |
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| Keywords: | Trivalent chromium Sulphate Hard chromium Electrodeposition Mechanism Coating Characterization. |
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