Electrochemical deposition of coloured Ni/Cu₂O bilayer films on large area plastic substrates for decorative applications

ABSTRACT

In this study, coloured Ni/Cu₂O bilayer films were electrochemically deposited on large area automobile plastic parts (7 × 13 cm) for decorative applications. Such coatings may become an alternative to ubiquitously used Cr coatings for plastics. Purple, dark cyan and gold colours with good homogeneity and high brightness could be produced by tuning the deposition time of the Cu₂O layer. Colouration of the bilayer film can be ascribed to interference of light through the metal/dielectric layer, where the thickness of the dielectric layer controls the wavelength of the reflected light. Cu₂O film has a compact structure and low roughness, which is essential to obtain uniform colours. Moreover, the Ni/Cu₂O bilayer exhibits good adhesion behaviour, environmental stability and enhanced corrosion resistance. This process is industrially viable and enables the large scale production of such decorative coatings.

KEYWORDS:

• Decorative coatings
• electrochemical deposition
• plastics
• structural colours
• Cu₂O

Acknowledgements

The authors acknowledge the financial support of Durden Plastic Products and Adhesive Films Inc. Also, they would like to thank Prof. Ersin Kayahan for his help with the reflectance measurements.

Disclosure statement

In accordance with Taylor & Francis policy and my ethical obligation as a researcher, I am reporting that Alime Colak and Huseyin Balci are current employees of Durden Plastic Products and Adhesive Films Inc., which both financially supported this work and has a business interest in the research reported in the enclosed paper.