Electrodeposited zinc composite coatings with embedded carbon nanotubes – advanced composite materials for better corrosion protection

ABSTRACT

The aim of the present investigation was to demonstrate a preparation method for obtaining an electrodeposited composite zinc coating with incorporated carbon nanotubes (CNT). The composite coatings were additionally treated in a newly developed conversion solution based on a Cr(III)-containing compound. The surface morphology of the Cr(III) and non-Cr(III) samples was investigated with scanning electron microscopy (SEM), the metallographic structure with X-ray diffraction analysis (XRD) and the composition with X-ray photoelectron spectroscopy (XPS). Composite zinc coatings without and with the surface conversion film (CF) have been investigated in a standard test medium of 5% NaCl solution by use of potentiodynamic polarisation (PDP) curves, electrochemical impedance spectroscopy (EIS) and polarisation resistance (R_p) measurements. The results obtained show the synergistic effect of the incorporated CNT and conversion film for achieving better corrosion resistance of the system composite Zn/CF in aggressive medium containing chloride ions as corrosion activators.

KEYWORDS:

• Composite Zn electrodeposits
• carbon nanotubes
• corrosion
• conversion film

Acknowledgements

Financial support of the Project ДН 09/6 “Design of innovative metal and hybrid zinc coatings for improvement of steel corrosion protection”, funded by the Fund for Scientific Researches in Bulgaria, is gratefully acknowledged by the authors. Joint Research Project “Innovative environmentally friendly protective systems on steel” between the Institute of Physical Chemistry and Ningbo Institute of Materials Technology and Engineering as a part of the Bilateral Agreement between the Bulgarian and Chinese Academies of Sciences is acknowledged as well.

Disclosure statement

No potential conflict of interest exist between the authors.