Effect of Pd Interlayer on Electrochemical Properties of ENIG Surface Finish in 3.5 wt.% NaCl Solution

• Published in: Journal of electronic materials 2014-09, Vol.43 (9), p.3307-3316
• Main Authors: Nam, N. D., Bui, Q. V., Nhan, H. T., Phuong, D. V., Bian, M. Z.
• Format: Article
• Language: English
• Subjects: Applied sciences; Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed matter: structure, mechanical and thermal properties; Corrosion; Corrosion prevention; Corrosion resistance; Diffusion in solids; Electronics and Microelectronics; Exact sciences and technology; Instrumentation; Liquid-solid equilibrium; Materials Science; Metals. Metallurgy; Microelectronics; Microscopy; Optical and Electronic Materials; Physics; Production techniques; Protective coatings; Solid State Physics; Surface treatment; Transport properties of condensed matter (nonelectronic)
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-014-3203-5

The corrosion resistance of a multilayered (NiP-Pd-Au) coating with various thicknesses of palladium (Pd) interlayer deposited on copper by an electroless method was investigated using electrochemical techniques including potentiodynamic polarization and electrochemical impedance spectroscopy. In addition, the surface finish was examined by x-ray diffraction analysis and scanning electron microscopy, and the contact angle of the liquid–solid interface was recorded. The corrosion resistance of the copper substrate was considerably improved by Pd interlayer addition. Increase of the thickness of the Pd interlayer enhanced the performance of the Cu-NiP-Pd-Au coating due to low porosity, high protective efficiency, high charge-transfer resistance, and contact angle. These are attributed to the diffusion of layers in the Cu-NiP-Pd-Au coating acting as a physical barrier layer, leading to the protection provided by the coating.