CIDEPINT   05376
CENTRO DE INVESTIGACIONES EN TECNOLOGIA DE PINTURAS
Unidad Ejecutora - UE
artículos
Título:
A conversion layer based on trivalent chromium and cobalt for the corrosion protection of electrogalvanised steel.
Autor/es:
J.D. CULCASI; ALEJANDRO R. DI SARLI; CÉLIA R. TOMACHUK; ISOLDA COSTA; CECILIA I. ELSNER
Revista:
SURFACE AND COATINGS TECHNOLOGY
Editorial:
ELSEVIER SCIENCE SA
Referencias:
Lugar: Amsterdam; Año: 2014 vol. 258 p. 426 - 436
ISSN:
0257-8972
Resumen:
The corrosion resistance of pure zinc coatings can be
improved through the application of suitable chemical passivation treatments.
Hexavalent chromium (Cr6+) compounds have widely been used to formulate conversion
layers providing better anticorrosive protection as well as anchorage
properties to painting systems. However, taking into account that they are
produced using hazardous chemical compounds, the development of alternative and
?green? technologies with equivalent protective performance is a paramount
purpose of many R&D laboratories working around the world. In the present
paper, the corrosion behavior of industrially electrogalvanized steel subjected
to a Cr+3 + Co+2-based passivation treatment was studied. The experimental work
involved electrochemical impedance spectroscopy (EIS) measurements and
polarization curves in a 0.1 mol/L Na2SO4 solution, surface microstructural and
morphological characterization by electronic microscopy as well as chemical analysis
by EDXS and XPS. The most commonly observed failures on the Cr6+ treated
samples were attributed to microstructural features of the substrate that were
not adequately healed by the Cr6+ passivation treatment.