Current Density Effect on Nickel Electroplating Using Post Supercritical CO2 Mixed Watts Electrolyte

Authors: Chun-Ying Lee, Mei-Wen Wu, Van Cuong Nguyen, Hung-Wei Chuang

Abstract:

In this study, a nickel film with nano-crystalline grains, high hardness and smooth surface was electrodeposited using a post supercritical carbon dioxide (CO2) mixed Watts electrolyte. Although the hardness was not as high as its Sc-CO2 counterpart, the thin coating contained significantly less number of nano-sized pinholes. By measuring the escape concentration of the dissolved CO2 in post Sc-CO2 mixed electrolyte with the elapsed time, it was believed that the residue of dissolved CO2 bubbles should closely relate to the improvement in hardness and surface roughness over its conventional plating counterpart. Therefore, shortening the duration of electroplating with the raise of current density up to 0.5 A/cm2 could effectively retain more post Sc-CO2 mixing effect. This study not only confirms the roles of dissolved CO2 bubbles in electrolyte but also provides a potential process to overcome most issues associated with the cost in building high-pressure chamber for large size products and continuous plating using supercritical method.

Keywords: Additive-free electrolyte, electroplating, nickel, supercritical CO2.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1087141

References:

[1] H. Yoshida, M. Sone, A. Mizushima, K. Abe, X.T. Tao, S. Ichihara, S. Miyata, Electroplating of nanostructured nickel in emulsion of supercritical carbon dioxide in electrolyte solution, Chemistry Letters, vol. 11, pp. 1086-1087, 2002.
[2] T.F.M. Chang, M. Sone, A. Shibata, C. Ishiyama, Y. Higo, Bright nickel film deposited by supercritical carbon dioxide emulsion using additive-free Watts bath, Electrochimica Acta, vol. 55, pp. 6469-6475, 2010.
[3] T.F.M. Chang, M. Sone, Function and mechanism of supercritical carbon dioxide emulsified electrolyte in nickel electroplating reaction, Surface and Coatings Technology, vol. 205, pp. 3890-3899, 2011.
[4] S.T. Chung, H.C. Huang, S.J. Pan, W.T. Tsai, P.Y. Lee, C.H. Yang, M.B. Wu, Material characterization and corrosion performance of nickel electroplated in supercritical CO2 fluid, Corrosion Science, vol. 50, pp. 2614-2619, 2008.
[5] S.T. Chung, W.T. Tsai, Nanocrystalline Ni-C electrodeposits prepared in electrolytes containing supercritical carbon dioxide, Journal of the Electrochemical Society, vol. 156, pp. D457-D461, 2009.
[6] N. Shinoda, T. Shimizu, T.F.M. Chang, A. Shibata, M. Sone, Filling of nanoscale holes with high aspect ratio by Cu electroplating using suspension of supercritical carbon dioxide in electrolyte with Cu particles, Microelectronic Engineering, vol. 97, pp. 126-129, 2012.
[7] V.V. Dhanuka, J.L. Dickson, W. Ryoo, K.P. Johnston, High internal phase CO2-in-water emulsions stabilized with a branched nonionic hydrocarbon surfactant, Journal of Colloid and Interface Science, vol. 298, pp. 406-418, 2006.
[8] V.C. Nguyen, C.Y. Lee, F.J. Chen, C.S. Lin, T.Y. Liu, Study on the internal stress of nickel coating electrodeposited in an electrolyte mixed with supercritical carbon dioxide, Surface and Coatings Technology, vol. 206, pp. 3201-3207, 2012.
[9] V.C. Nguyen, C.Y. Lee, L. Chang, F.J. Chen, C.S. Lin, The relationship between nano crystallite structure and internal stress in Ni coatings electrodeposited by Watts bath electrolyte mixed with supercritical CO2, Journal of the Electrochemical Society, vol. 159, pp. D393-D399, 2012.
[10] C.V. Nguyen, C.Y. Lee, F.J. Chen, C.S. Lin, L. Chang, An electroplating technique using the post supercritical carbon dioxide mixed electrolyte, Surface & Coating Technology, in press, http://dx.doi.org/10.1016 /j.surfcoat.2013.05.016, 2013.
[11] J. Eigeldinger, H. Vogt, The bubble coverage of gas-evolving electrodes in a flowing electrolyte, Electrochimica Acta, vol. 45, pp. 4449-4456, 2000.
[12] R. Weil, Origins of stress in electrodeposits- part I, Plating, vol. 57, pp. 1231-1237, 1970.
[13] S.H. Kim, H.J. Sohn, Y.C. Joo, Y.W. Kim, T.H. Yim, H.Y. Lee, and T. Kang, Effect of saccharin addition on the microstructure of electrodeposited Fe-36 wt% Ni alloy, Surface and Coating Technology, vol. 199, pp. 43-48, 2005.
[14] C.V. Thompson, Structure evolution during processing of polycrystalline films, Annual Review of Materials Science, vol. 30, pp. 159-190, 2000.
[15] J.K. Dennis, and T.E. Such, Nickel and Chromium Plating, Wiley, 1972.