The effect of curing time and curing temperature on the corrosion behavior of nanosilica modified potassium silicate coatings on AA2024

Nanosilica modified potassium silicate conversion coatings were deposited on the surface of 2024 aluminum alloy. The corrosion behavior of coatings was studied by electrochemical impedance spectroscopy, potentiodynamic polarization and the surface analyzing techniques. The effect of curing time and the curing temperature was studied on anti-corrosion behavior of coatings. Curing temperature showed a significant effect in silicate conversion coating and higher corrosion resistance was obtained with 150 °C curing temperature. Also the experimental results indicated that the corrosion resistance was increased with increasing the curing time. This behavior can be related to the increase of the silicate coating continuity and reinforcement of the siloxane chains which formed on the surface. Surface analysis results indicated that the coating obtained from 2.33 silica ratio was more uniform and continuous.