The Characteristics of Nickel-Electroplating on Copper Substrate in CO2 Supercritical Fluid
In this work, a nickel electroplating was performed on the copper substrate using nonionic surfactant in supercritical carbon dioxide to improve the dispersion characteristics of nickel nano-particles. The electric resistance of emulsion decreased rapidly from 46 to 25 Ω with an increasing pressure from 8 MPa to 16 MPa and was nearly constant at 25 Ω over 14 MPa. The conductivity of emulsion solution was highest at nonionic surfactant concentration of 0.1 vol% and the dispersion of nickel nano-particles was better than at any other concentration. CO2 concentration was controlled under 0.5 vol% to reduce electric resistance in emulsion solution. Roughness (Ra) of copper substrate without plating was 0.084 ㎛, however, that of nickel film plated for 10 min was smoothed to 0.020 ㎛ and the surface of nickel film plated was smoothed with an increasing plating time. The plating properties of nickel in CO2 supercritical fluid showed better properties than in conventional method.
M. Gupta and Christina Y.H. Lim
K.-M. Hong et al., "The Characteristics of Nickel-Electroplating on Copper Substrate in CO2 Supercritical Fluid", Journal of Metastable and Nanocrystalline Materials, Vol. 23, pp. 247-250, 2005