International. Brazilian scientists investigated organic coatings based on epoxy and polyurethane matrices containing polyaniline dodecyl benzene sulfonic acid (Pani-Dbsa).
The coatings were prepared and applied on steel plates (SAE 1020). The plates were subjected to a salt spray chamber for up to 30 days, in order to assess the corrosion protection of these coatings.
The scientists analyzed the properties of coated plates as a function of time using electrochemical impedance spectroscopy, open circuit potential, optical microscopy, and Raman spectroscopy.
The results indicated a decrease in electrical resistance, an increase in capacitance and a decrease in open circuit potential.
According to the scientists, epoxy-based coatings performed better when Pani-DBSA was used as a pigment, while in polyurethane coatings Pani-DBSA appears to have an adverse effect. Raman spectroscopy indicates possible chlorination of the epoxy matrix after 30 days of exposure to the saline chamber.
