Hybrids Films Obtained on ZnNi Substrates: Effect of Withdrawal Speed

Abstract

Due to the environment and economical questions, the use of cadmium coatings, in the aeronautical and automotive industries, has been prohibited. In this context, ZnNi coating alloys have been propose to replace cadmium coatings due to its properties. However, in order to postpone the corrosion of ZnNi alloy, hybrids films obtained by sol-gel process have been studied. In this work, hybrids films were obtained on ZnNi coating by dip-coating process from a sol constituted of alkoxide precursors: γ-methacryloxypropyl-trimethoxysilane and tetraethoxysilane with cerium nitrate addition (0.01 M). Two withdrawal speeds of substrates from the sol were applied: 5 cm.min-1 and 10 cm.min-1 .The films obtained were evaluated by morphological (SEM and AFM) and electrochemical characterization. The superior corrosion protection performance was observed for the ZnNi/hybrid film system obtained with withdrawal speed of 10 cm.min-1, thought, the presence of discontinuities were observed in this film.