Effect of Phenol Resin Addition on Corrosion Resistance of Aluminum Sheet Coated with Epoxy Resin Using Electrodeposition Process

Effect of phenol resin addition on corrosion resistance of aluminum sheet coated with epoxy resin using electrodeposition process has been investigated. Corrosion test results revealed that the weight loss of the aluminum sheet in 1wt% NaCl solution (311K, pH3.0) decreased with an increase of phenol resin addition to epoxy resin. It was found that glass transition temperature (Tg) and effective network density (ν) of the electrodeposition film were independent of phenol resin addition, but that water absorption and water permeability decreased with an increase of phenol resin addition. Water permeability was correlated well with the corrosion resistance. Corrosion behavior of epoxy resin coated aluminum is discussed in terms of physical properties of electrodeposition film against water in the coating film.