离子液体中18-冠醚-6添加剂对三价铬电沉积的影响
Effect of 18-Crown-6 Additive on Chromium Electrodeposition in Ionic Liquid
Received date: 2019-10-15
Revised date: 2020-02-27
Online published: 2020-12-28
在1-丁基-3-甲基咪唑硫酸氢盐（[BMIM]HSO4）电镀液中,探究了18-冠醚-6添加剂对电沉积铬的影响. 紫外-可见光谱结果表明,18-冠醚-6与Cr3+形成配合物,使最大吸收波长发生红移. 循环伏安研究表明,Cr3+的还原经历了两步. 18-冠醚-6的添加使Cr3+的峰电位和起始还原电位均正移了220 mV. 能谱仪（EDS）结果显示,在18-冠醚-6的作用下镀层中铬含量有所提高. 铬镀层的扫描电子显微镜（SEM）表征结果表明,加入18-冠醚-6后,所得镀层的颗粒变大. 18-Crown-6/CrCl3/[BMIM]HSO4/H2O电镀液中工艺优化的结果为：在温度为50 oC、pH值为3.5、电流密度为1200 A·m-2、电镀时间为1.5 h的最佳工艺条件下,铬镀层的厚度达到72.5 μm,电流效率为42.3%.
关键词： 三价铬; 1-丁基-3-甲基咪唑硫酸氢盐; 18-冠醚-6; 铬镀层; 电流效率
王怡捷 , 钮东方 , 张新胜 . 离子液体中18-冠醚-6添加剂对三价铬电沉积的影响[J]. 电化学, 2020 , 26(6) : 859 -867 . DOI: 10.13208/j.electrochem.191009
Trivalent chromium ion (Cr3+) is used for electrodeposition due to its low toxicity. Electrodeposition in ionic liquids can greatly solve for hydrogen evolution problem. However,as a widely used Cr(III) precursor, chromium chloride hydrate (CrCl3·6H2O), still contains water. In the presence of water, Cr3+ will form a complex coordination structure with water molecules ([Cr(H2O)6]3+), which is a stable octahedral structure and is difficult to be directly reduced to chromium metal. Therefore, coordination agents should be added into the bath. In this work, the effect of 18-Crown-6 additive on chromium electrodeposition was investigated in CrCl3/[BMIM]HSO4/H2O plating solution. The UV-Vis spectra showed that 18-Crown-6 formed a complex with Cr3+, destroyed the stable coordination structure formed by Cr3+ and water molecules, making a red shift in the maximum absorption wavelength. The cyclic voltammograms indicated that the electroreduction of Cr3+ occurred in a two-step process, namely, Cr3+ + e → Cr2+ and Cr2+ + 2e → Cr0. Both of the peak potential and initial reduction potential of Cr3+ had positive shifts by 220 mV after adding 18-Crown-6. The reason for this phenomenon was that when 18-Crown-6 was added to the plating solution, the stable structure of [Cr(H2O)6]3+ was destroyed, Cr3+ became more readily to be reduced, thereby, lowered the reduction potential of Cr3+. The EDS data showed that the chromium content in the coating was increased under the action of 18-Crown-6. The improvement indicated that 18-Crown-6 was beneficial to the chromium electrodeposition. The SEM characterizations indicated that the coating obtained in 18-Crown-6/CrCl3/[BMIM]HSO4/H2O plating solution had a larger particle size. Tafel curves suggested that the corrosion resistance of chromium coating was better than that of brass substrate. The optimized process in 18-Crown-6/CrCl3/[BMIM]HSO4/H2O plating solution could be proceeded at the temperature of 50 oC, pH of 3.5, current density of 1200 A·m-2, and plating time of 1.5 h. The thickness of the chrome plating reached 72.5 μm and the current efficiency was 42.3%.
| [1] | Giovanardi R, Orlando G.Chromium electrodeposition from Cr(III) aqueous solutions[J]. Surface & Coatings Technology, 2011, 205(15): 3947-3955. |
| [2] | Soragni E, Fontanesi C, Barani G, et al.Dynamic aspects of the electroreduction of chromic acid solutions[J]. Journal of Applied Electrochemistry, 2000, 30(9): 1069-1079. |
| [3] | Lu C E, Pu N W, Hou K H, et al.The effect of formic acid concentration on the conductivity and corrosion resistance of chromium carbide coatings electroplated with trivalent chromium[J]. Applied Surface Science, 2013, 282: 544-551. |
| [4] | de Lima-Neto P, da Silva G P, Correia A N. A comparative study of the physicochemical and electrochemical properties of Cr and Ni-W-P amorphous electrocoatings[J]. Electrochimica Acta, 2006, 51(23): 4928-4933. |
| [5] | Zeng Z X, Sun Y L, Zhang J Y.The electrochemical reduction mechanism of trivalent chromium in the presence of formic acid[J]. Electrochemistry Communications, 2009, 11(2): 331-334. |
| [6] | Abbott A P, Ryder K S, Konig U.Electrofinishing of metals using eutectic based ionic liquids[J]. Transactions of The Institute of Metal Finishing, 2008, 86(4): 196-204. |
| [7] | Eugenio S, Rangel C M, Vilar R, et al.Electrochemical aspects of black chromium electrodeposition from 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid[J]. Electrochimica Acta, 2011, 56(28): 10347-10352. |
| [8] | Saravanan G, Mohan S.Corrosion behavior of Cr electrodeposited from Cr(VI) and Cr(III)-baths using direct(DCD) and pulse electrodeposition(PED) techniques[J]. Corrosion Science, 2009, 51(1): 197-202. |
| [9] | Del Pianta D, Frayret J, Gleyzes C, et al.Determination of the chromium(III) reduction mechanism during chromium electroplating[J]. Electrochimica Acta, 2018, 284: 234-241. |
| [10] | Abbott A P, McKenzie K J,. Application of ionic liquids to the electrodeposition of metals[J]. Physical Chemistry Chemical Physics, 2006, 8(37): 4265-4279. |
| [11] | Galiński M, Lewandowski A, St?pniak I.Ionic liquids as electrolytes[J]. Electrochimica Acta, 2006, 51(26): 5567-5580. |
| [12] | Rao Zh, Feng K, Tang B B, et al.Surface decoration of amino-functionalized metal-organic framework/graphene oxide composite onto polydopamine-coated membrance substrate for highly efficient heavy metal removal[J]. ACS Applied Materials & Interfaces, 2017, 9(3): 2594-2605. |
| [13] | Abbott A P, Capper G, Davies D L, et al.Electrodeposition of chromium black from ionic liquids[J]. Transactions of the IMF, 2004, 82(1/2): 14-17. |
| [14] | He X K, Li C, Zhu Q Y, et al.Electrochemical mechanism of Cr(III) reduction for preparing crystalline chromium coatings based on 1-butyl-3-methylimidazolium hydrogen sulfate ionic liquid[J]. RSC Advances, 2014, 4(109): 64174-64182. |
| [15] | Surviliené S, Nivinskiené O, ?e?uniené A, et al.Effect of Cr(III) solution chemistry on electrodeposition of chromium[J]. Journal of Applied Electrochemistry, 2006, 36(6): 649-654. |
| [16] | El-Sharif M, Mcdougall J, Chisholm C.Electrodeposition of thick chromium coatings from an environmentally acceptable chromium(III)-glycine complex[J]. Transactions of the IMF, 1999, 77(4): 139-144. |
| [17] | Protsenko V, Gordiienko V, Butyrina T, et al.Hard chromium electrodeposition from a trivalent chromium bath containing water-soluble polymer[J]. Turkish Journal of Chemistry, 2014, 38(1): 50-55. |
| [18] | Su N, Bradshow J S, Zhang X X, et al.Syntheses and metal ion complexation of novel 8-hydroxyquinoline-containingdizaz-18-crown-6 ligands and analogues[J]. Journal of Organic Chemistry, 1999, 64(24): 8855-8861. |
| [19] | Tu C Q, Surowiec K, Bartsch R A.Novel calix[4]arenethiacrown ether for selective and efficient extraction of Ba(II), Pb(II), and Hg(II)[J]. Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2007, 58(3/4): 361-366. |
| [20] | Tsukube H, Shinoda S, Mizutani Y, et al. Enhanced Li+ ion-selective ionophoric properties of double armed diaza-l2-crown-4 derivatives[J]. Tetrahedron, 1997, 53(10): 3487-3496. |
| [21] | Kim K S, Shin B K, Lee H.Physical and electrochemical properties of 1-butyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium iodide, and 1-butyl-3-methylimidazolium tetrafluoroborate[J]. Korean Journal of Chemical Engineering, 2004, 21(5): 1010-1014. |
| [22] | He X K, Zhu Q Y, Hou B L, et al.Electrodeposition of nanocrystalline chromium coatings from 1-butyl-3-methy limidazolium-hydrogen sulfate ionic liquid[J]. Surface and Coatings Technology, 2015, 262: 148-153. |
| [23] | Sun L Y, Brennecke J F.Characterization of imidazolium chloride ionic liquids plus trivalent chromium chloride for chromium electroplating[J]. Industrial & Engineering Chemistry Research, 2015, 54(17): 4879-4890. |
| [24] | Survilien$\acute{e}$ S, Eugenio S, Vilar R.Chromium electrodeposition from [Bmim][BF4] ionic liquid[J]. Journal of Applied Electrochemistry, 2011, 41(1): 107-114. |
/
| 〈 |
|
〉 |
