Estudo de filmes polimericos contendo silanos y-UPS e VS como revestimentos promotores de adesão em superficies galvanizadas e eletrodepositos de ligas ZN/FE e ZN/Co / Study of the films content y-UPS and VS as adhesion promoters coatings on galvanized surfaces and Zn/Fe-Zn/Co alloys electrodepositions

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The Zinc s excellent resistance, as used in differents corrosive environments, and its hability to protect steel, make galvanized steel (HDG) and Zinc electrodepositions very usual materiaIs in the automotive and construction industries. Galvanized steel and Zinc electrodepositions substrates need, however, to be protected from strongly corrosive environments by organic coatings (painting). Zinc/paint system weak adhesion results in a relatively cheap and effective zinc substrate pretreatment, however toxic to humam being, and also to the environment. Organofunctional silanes appear as an altemative to substitute this pretreatment, without making use of hexavalent chromium ( CR POT. +6 ), because they are bifuncional molecules that can act as adhesion promoters and surface protectors. The main benefit to employ them is to promote adhesion between organic (painting) and inorganic (metals) materiaIs. The GalvanizedlSilane and Electrodeposition Alloys/Silane systems had been studied in this essay. Techniques like EIS (Electrochemical Impedance Spectroscopy), XPS (X-Ray Emission Photoeletric Spectrometry), Contact Angle and microscopical analyses were used in this work. The barrier for resistance was evaluated through Electrochemical Impedance Spectroscopy in a 0,1M NaCI solution comparing coatings performances. Curing caused as importante modification in the impedance diagrams, as well as other variables like concentration, hydrolysis time, silane types and different substrates. The results indicate the Zn/Co alloy coated for VS and Zn/Fe alloy coated for gama -UPS as the systems most promising

ASSUNTO(S)

galvanized stell espectroscopia de impedancia ligas de zinco electrochemical impedance aço galvanizado zinc alloys silano silane

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