Electrochemical properties and thermal stability of epoxy coatings electrodeposited on aluminium and modified aluminium surfaces

• Main Authors: ZORICA M. KACAREVIC-POPOVIC, ZORICA Z. LAZAREVIC, VESNA B. MISKOVIC-STANKOVIC
• Format: Article
• Language: English
• Published: Serbian Chemical Society 2001-12-01
• Series: Journal of the Serbian Chemical Society
• Subjects: electrodeposition; epoxy coatings; aluminium; anodized aluminium; phosphatized and chromatized- phosphatized aluminium; corrosion; EIS
• Online Access: http://www.shd.org.yu/HtDocs/SHD/Vol66/No11-12/V66-No-11-12-12.pdf

The corrosion behaviour of epoxy coatings electrodeposited on aluminium, as well as on electrochemically and chemically modified aluminium were investigated during exposure to 3 % NaCl. Electrochemical impedance spectroscopy (EIS) and thermogravimetric analysis (TGA) were used for the determination of the protective properties of epoxy coatings on aluminium, anodized aluminium, phosphatized and chromatized-phosphatized aluminium. The protective properties of epoxy coatings on anodized and chromatized-phosphatized aluminium are significantly improved with respect to the same epoxy coatings on aluminium and phosphatized aluminium: higher values of the pore resitance and charge-transfer resistance, lower values of the coating capacitance, double-layer capacitance and relative permittivity (from EIS) smaller amount of absorbed water inside the coating (From TGA). On the other hand, the lower values of the ipdt temperature indicate a lower thermal stability of the epoxy coatings on anodized and chromatized-phosphatized aluminium.