Generation of conversion coatings using rare earths on galvanised steel

Authors

  • M. A. Arenas Departamento de Corrosión y Protección. Centro Nacional de Investigaciones Metalúrgicas (CSIC)
  • J. J. Damborenea Departamento de Corrosión y Protección. Centro Nacional de Investigaciones Metalúrgicas (CSIC)

DOI:

https://doi.org/10.3989/revmetalm.2005.v41.iExtra.1070

Keywords:

Conversion coatings, Cerium, Inhibitors

Abstract


Cerium conversion coatings are formed on commercial galvanized steel and a generation mechanism is suggested. The best conversion coatings were found using 10,000 ppm CeCl3·7H2O + 0,3 % vol. of H2O2 with a pH of 1.3. A cathodic potential, -100 mV versus corrosion potential, was applied during the treatment at a constant temperature of 43 °C. SEM micrographs have revealed a non uniform coating thickness between 1-2 μm. Polarization curves in 3.56 wt. % NaCl exhibited an inhibition power of about 94 % with respect to the galvanized steel. The proposed mechanism suggests that the Ce (III) ions in the solution were oxidized by H2O2 to Ce (IV) which then precipitated as CeO2. The applied voltage could cause a higher presence of Ce3+ in the film maybe due to an electroreduction process of cerium (IV) in the film to cerium (III).

Downloads

Download data is not yet available.

Downloads

Published

2005-12-17

How to Cite

Arenas, M. A., & Damborenea, J. J. (2005). Generation of conversion coatings using rare earths on galvanised steel. Revista De Metalurgia, 41(Extra), 433–437. https://doi.org/10.3989/revmetalm.2005.v41.iExtra.1070

Issue

Section

Articles