INVESTIGADORES
ELSNER Cecilia Ines
congresos y reuniones científicas
Título:
Galvanized steel protection evaluation by electrochemical methds
Autor/es:
C.R. TOMACHUK; A.R. DI SARLI; C.I. ELSNER; O.B. FERRAZ
Lugar:
Recife - Pernambuco
Reunión:
Congreso; 2nd International Corrosion Meeting - INTERCORR 2008; 2008
Institución organizadora:
Asociación Brasilera de Corrosión
Resumen:
In the last 30 years, zinc plating had remarkable
development due to the increasing demand for coatings with better corrosion
resistance from the automotive industry. The corrosion resistance of these
coatings can be improved by means of suitable chemical passivation treatments.
Hexavalent chromium compounds have been used to create conversion layers on Zn
providing better anticorrosive protection as well as anchorage properties to
painting systems. However, new and more severe environmental regulations impose
elimination of hexavalent chromium compounds on passivation baths and its
replacement by environmentally friendly chemicals. In this work, the
electrochemical behaviour of electrogalvanized steel with Cr3+ based
passivation layer and of zinc with organic fillers coatings were studied, and
their corrosion response compared with that exhibited by electrogalvanized
steel protected with traditional Cr6+ conversion
treatment. The corrosion behaviour was investigated through polarization curves
and electrochemical impedance spectroscopy in NaCl 3.5% wt solution at room
temperature. Morphological observations on the coatings surfaces were also
performed. The experimental results allow inferring that the zinc+polymer
coating system investigated in this study shows a corrosion resistance superior
to that presented by the Cr3+ protected coating
and comparable to that exhibited by the coating protected by the Cr6+ conversion
treatment, suggesting that it can be a non-polluting alternative to replace
this latter system.