engleski

Testing effectiveness of coatings based on TiO2 nanoparticles for corrosion protection of stainless steel

In corrosive atmospheric environments containing chlorides, widely utilized AISI 304 stainless steel does not exert sufficient resistance towards corrosion. On existing stainless steel structures where replacement of constructional elements with those built of more resistant stainless steels is impossible or economically unviable, the surface of steel may additionally be protected by coatings. This study focuses on applicability of water-based coatings containing TiO2 nanoparticles for corrosion protection of AISI 304 stainless steel. To produce titanium dioxide(TiO2) nanoparticle coatings, it is desirable that nanoparticles dispersed into a liquid solution and remain stable for a certain period of time. Controlling the dispersion and aggregation of the nanoparticles is crucial to exploiting the advantages of the nanometer-sized TiO2 particles. For that purpose, the investigated coating formulations contained various organic compounds in order to prevent the tendency of agglomeration of nanoparticles in aqueous medium. Aqueous dispersion of TiO2 nanoparticles are characterized by FTIR analysis to confirm the adsorption of organic compounds on the surface of TiO2 nanoparticles which should allow successful dispersion and electrostatic stability of nanoparticles in aqueous solution. Time stability of aqueous dispersions of TiO2 nanoparticles is determined by spectrophotometric method of measuring absorbance in visible part of spectrum. Coatings were applied to samples by the technique of aerial spraying under pressure and dip coating. The measurements of: corrosion potential, cyclic polarization and electrochemical impedance spectroscopy were done in order to determine which formulation of nanostructured coating provides the best protection against corrosion on AISI 304 stainless steel. The role of photocatalytic activity of TiO2 nanoparticles in corrosion protection is also discussed.

stainless steel; corrosion; TiO2 nanostructured coating

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