Journal of the Brazilian Chemical Society
On-line version ISSN 1678-4790
LEITE, Adriana O. S. et al. Evaluation of the anticorrosive properties of environmental friendly inorganic corrosion inhibitors pigments. J. Braz. Chem. Soc. [online]. 2005, vol.16, n.4, pp.756-762. ISSN 1678-4790. http://dx.doi.org/10.1590/S0103-50532005000500013.
Anticorrosive properties of the following environmental friendly inorganic pigments were evaluated: zinc phosphate (ZP), zinc molybdate (ZM), zinc calcium molybdate (ZCM), zinc phosphomolybdate (ZPM) and zinc calcium phosphomolybdate (ZCPM). AISI 1010 steel samples were immersed in 10-2 mol dm-3 NaCl aqueous solution saturated with one of the pigments, followed by mass loss measurements, by monitoring the open circuit potential with immersion time and by potentiodynamic linear polarization at 1 mV s-1. The corrosion products on the steel surface were characterized by Scanning Electron Microscopy, Energy Dispersive X-ray and X-rays Diffraction analyses. All the pigments inhibited the corrosion of steel. The films formed on the steel surface protect the substrate against corrosion. The results suggest a synergic effect of phosphate and molybdate compounds in the phosphomolybdate-based pigments, improving the corrosion resistance of steel. The ZMP and ZCPM decreased the corrosion rate by a factor of 2.15 and 3.50, respectively.
Keywords : steel; corrosion; anticorrosive pigments; mass loss; electrochemical tests; surface analysis.