HETEROPOLYSILOXANE COATINGS ON ELECTROGALVANIZED STEEL - ELABORATION AND CHARACTERIZATION

Heteropolysiloxane coatings were deposited on an electrogalvanized ste el substrate by the dip-coating sol-gel technique. Different coating s ols using two precursors, aminopropyltriethoxysilane and methyltrietho xysilane, diluted in a water/ethanol mixture with or without the prese nce of catalyst, were prepared. Thus, coatings incorporating into thei r structure, both amine and methyl groups of hydrophilic and hydrophob ic character, respectively, were obtained. The characterization of the coatings was monitored at the various stages from the sol state to th e solid state using several techniques, namely Si-29 NMR, SEM, EMPA, X PS, FTIR and Raman spectroscopies, and the mechanical three-point flex ure test. The capability of heteropolysiloxane coatings to protect the electrogalvanized steel substrate against humid corrosion and to act as an adhesion promoter has been investigated.