Acta Phys. -Chim. Sin. ›› 2011, Vol. 27 ›› Issue (01): 143-148.doi: 10.3866/PKU.WHXB20110118

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

Copper Electrodeposition from Non-Cyanide Alkaline Baths Containing Methylene Diphosphonic Acid as a Complexing Agent

ZHENG Jing-Wu, LU Guo-Ying, QIAO Liang, JIANG Li-Qiang, JIANG Mei-Yan   

  1. College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032, P. R. China
  • Received:2010-07-20 Revised:2010-11-02 Published:2010-12-31
  • Contact: JIANG Li-Qiang E-mail:jiliqi@zjut.edu.cn
  • Supported by:

    The project was supported by the Natural Science Foundation of Zhejiang Province, China (Y406406).

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Abstract:

A cyanide-free alkaline copper deposition bath was developed using methylene diphosphonic acid (MDPA, H4L) as a complexing agent for Cu2+. The plating bath was investigated using potentiometric titrations, voltammetric curves, and polarization curves. The potentiometric titration gave dissociation constants for MDPA of: pK1=1.86, pK2=2.65, pK3=6.81, pK4=9.04, and the stability constants were: pKML= 10.65, pKML2 = 5.59, pKML3 = 2.50. Three different complex species were present in the bath as the pH increases: Cu(H3L)2, [Cu(H3L)(H2L)]-, and [Cu(H2L)2]2-. MDPA was found to be more likely to form complex species with Cu2+ than 1-hydroxyethylene-1,1-diphosphonic acid (HEDPA) from pH 7 to pH 10. At pH 9, [Cu(H3L)(H2L)]- and [Cu(H2L)2]2- were reduced to Cu at the cathode. Compared with the HEDPA system at 10 °C the peak potential shifted to more negative values and the rate of diffusion was faster.

Key words: Non-cyanide bath, Methylene diphosphonic acid, Copper electrodeposition, pH potentiometric titration, 1-Hydroxyethylene-1,1-diphosphonic acid