Effect of Current Density on Morphology and Corrosion Resistance of Epoxy Resin /Zn Layers

Abstract

In this research we intended to obtain and characteriz composite layers by using epoxy resin (disperse phase) electrodeposited with zinc (metal matrix). The epoxy resin/Zn layers were electrodeposited at two values of current densities: 3 A/dm² and 5 A/dm² from a suspension of epoxy resin particles with two mean diameter size particles (0.1-5.0 μm and 6-10 μm) in aqueous zinc sulphate electrolyte. Suspension was prepared by adding 10 g/L epoxy resin particles into electrolyte solution. The morphology of the layers was investigated by scanning electron microscopy method. The regular crystal structure characteristic of electroplated zinc layers was disturbed by epoxy resin particles that perturb the zinc growth during electrodeposition. The corrosion behavior of the layers in the corrosive solution was investigated by potentiodynamic polarization method. As corrosion test solution 0.5 M sodium chloride was used. The rate of corrosion for layers obtained at 3 A/dm² was 6.21 µm/year for layers with means diameter size particles of 0.1-5.0 μm, respectively 16.18 µm/year for layers with means diameter particles size of 6-10 μm. It was observed that by increasing the current density to 5 A/dm² the rate of corrosion for layers was 16.11 µm/year for layers with means diameter size particles of 0.1-5.0 μm, respectively 24.37 µm/year for layers with means diameter size particles of 6-10 μm.