J. Mater. Sci. Technol. ›› 2019, Vol. 35 ›› Issue (8): 1797-1802.DOI: 10.1016/j.jmst.2019.03.019

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A new insight into promotion action of Co2+ in Ni-diamond composite electrodeposition

Haifei Zhoua*(), Nan Dub, Jingdong Guoc, Shuan Liud   

  1. a Zhejiang Electric Power Corporation Research Institute, Hangzhou 310014, China
    b Nanchang Hangkong University, Nanchang 330063, China
    c Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
    d Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
  • Received:2018-09-29 Revised:2018-11-09 Accepted:2018-11-29 Online:2019-08-05 Published:2019-06-19
  • Contact: Zhou Haifei
  • About author:

    1The authors contributed equally to this work.

Abstract:

A new insight into the promotion action of Co2+ on both particle and metal deposition in Ni-diamond composite electrodeposition system was analyzed according to electrochemical measurements. The results showed that the addition of Co2+ made particles content in deposits increased remarkably. The change of particles content in deposits was related inversely to the change of cathodic zero potential with the increase of the concentration of cobalt sulfate. Zero charge potential of cathode was shifted to much more negative region. The negative shift of the zero potential, combining with positive shift of the zeta potential, increased the electrostatic force between the particle-adsorbed metallic cations and the cathode. It not only benefits to the transportation of particles in solution towards cathode, but also shortens their residence time on cathodic surface. Meanwhile, entry of particles is also promoted. For metals deposition, reduction resistance of metallic cations rises greatly and deposition current at cathodic potentiodynamic polarization decreases after cobalt sulfate has been added into electrolyte. These factors are favorable for increasing particles content in deposits. In addition, physical model of diamond particles deposition state before and after the addition of Co2+ has been discussed.

Key words: Cobalt sulfate, Composite electrodeposition, Ni-diamond, Zero charge potential, Particle content in deposits