Evaluation of the electrochemical behavior of TiO2/Al2O3/PCL composite coatings in Hank's solution

Highlights: • The diffusion of species through thickness was the governing mechanism observed. • Porous network formation in microstructure was improved by the powder addition. • TiO₂-Al₂O₃/PCL coatings improved corrosion protection to the metallic substrate. -- Abstract: This study focuses in the TiO₂/Al₂O₃ powders synthesized by the sol-gel at low vacuum atmosphere, incorporated to polycaprolactone polymer. The corrosion study of coating was realized by electrochemical techniques. The precursors for synthesis of TiO₂/Al₂O₃ powders were titanium and aluminum isopropoxides. The obtained powders were sintered at 350 °C and 1100 °C, then, they were mixed within polycaprolactone matrix. Results showed the rutile and corundum crystalline phases at 1100 °C. Electrochemical results showed a corrosion resistance improvement by the composite coatings, followed by formation and growing of the porous network. The corrosion behavior was governed by diffusion mechanism through the coating thickness. Scanning Electron Microscopy Characterization complemented the coating evaluation.