Abstract

GUZMAN ROSAS, ANDRES ALBERTO  and  OCAMPO C., LUZ MARINA. EVALUATION OF THE CORROSION RESISTANCE OF SYSTEMS EPOXY ZINC RICH PRIMER/POLYSILOXANE TOPCOAT BY MEANS OF ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY. Dyna rev.fac.nac.minas [online]. 2011, vol.78, n.167, pp.87-95. ISSN 0012-7353.

In this work was studied the epoxy zinc rich primer / polysiloxane topcoat system on hot rolled carbon steel. This system was exposed in accelerated corrosion testing chambers (total immersion, salt fog, corrosion cycle and prohesion) for 5000 hours. The specimens under study were evaluated every 20 days by electrochemical impedance spectroscopy and at the end of the test were performed visual checks and optical microscopy to see la morphology of the metal- coating interface and Raman microspectroscopy to identify the presence of corrosion products. The impedance results were simulated by equivalent electrical circuits. The modules impedance were about 10¹¹ W.cm² in prohesión, 10¹⁰ W.cm² in corrosion cycle, 10⁹ W.cm² in salt fog and in total inmersion (10^-2M NaCl and Na₂SO₄ 10^-2 M). This system had an excellent behavior during the test, with high resistance of film and charge transfer and low capacitance of film and double layer.

Keywords : accelerated test; corrosion; impedance; polysiloxane; zinc rich epoxy.

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