Patricia H. Suegama

Electrochemical behavior of carbon steel pre-treated with an organo functional bis-silane filled with copper phthalocyanine

The bis-[trimethoxysilylpropyl]amine (BTSPA) film filled with copper phthalocyanine (Cu-Ph) was prepared by adding different concentrations of copper phthalocyanine - Cu-Ph and deposited on a carbon steel substrate using 120 oC and 150 oC as curing temperatures. For samples cured at 150 oC a second layer was also deposited. The electrochemical behavior of carbon steel coated with BTSPA filled with Cu-Ph was studied by electrochemical measurements, electrochemical impedance spectroscopy (EIS) and polarization curves, in aerated 0.1 mol L-1 NaCl solution. Physical and chemical characterization was made by thermogravimetric analysis (TGA), scanning electron microscopy, contact angle measurements and infrared spectroscopy. TGA showed no decomposition of Cu-Ph during the curing process. Cu-Ph added into the silane film showed a strong influence on its corrosion resistance, mainly when the samples are cured at 150 oC. The results showed that lower inhibitor concentrations led to a higher corrosion resistance and the second layer increased by one order of magnitude the corrosion resistance.

Study of the Influence of the Rare Earth Elements (Ce3+ and Ce4+) Concentration on the Siloxanes Coating Applied on the Copper Surface

This work studied the influence of the rare earth (Ce3+ and Ce4+) elements concentration in polysiloxane films deposited on copper by dip-coating process, and evaluated their resistance in a 3.5 wt.% NaCl medium. Classical electrochemistry techniques were used as open circuit potential, polarization curves and electrochemical impedance spectroscopy. The results revealed that by adding low concentration of Ce4+ ions, the coating prevents the electrolyte uptake any longer retarding the substrate degradation consequently.