Corrosion protection of electrogalvanised steel by application of non-conducting polyaniline-silica particles

ABSTRACT

The authors have demonstrated that incorporation of poly(ethyleneimine) (PEI) coated polyaniline-silica (PANI-SiO₂) particles into the zinc coating matrix improves the corrosion resistance of low carbon steel in a 5% NaCl solution compared to the bare zinc coating. The zinc and hybrid coatings were electrodeposited on a steel cathode surface at pH 5.5 when PANI manifests itself as non-conductive emeraldine base. Scanning electron microscopy showed that the hybrid coating consists of particle agglomerates in size 50–100 μm, mixed with smooth formations and smaller needle-like particles. The influence of PEI is suggested to cause the appearance of the smooth formations. The influence of PANI-SiO₂ particles on the cathodic deposition and anodic dissolution has been checked with cyclic voltammetry. The protective properties of the coatings were characterised by potentiodynamic polarisation and polarisation resistance studies. X-ray diffraction and X-ray photoelectron spectroscopy were also applied to investigate the metallographic structure and chemical composition of the coatings.

KEYWORDS:

• Zinc coatings
• polyaniline particles
• hybrid coatings
• corrosion
• polyelectrolyte adsorption
• stabilisation of suspensions

Acknowledgements and funding

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 Bulgarian National Science Fund (BNSF) is gratefully acknowledged by the authors.

Disclosure statement

No potential conflict of interest was reported by the author(s).