Abstract

OLIVA, Alejandra; CODEGHINI, Licel; QUIROZ, Rosdely  and  ROSALES, Adalberto. Use of polyaniline films (PANI) on carbon steelas corrosion protector and hydrogen sensor. Rev. Fac. Ing. UCV [online]. 2011, vol.26, n.4, pp.89-100. ISSN 0798-4065.

The electrodeposition of polyaniline (PANI) on carbon steel plates (AISI 1010) was performed in order to study the PANI’s behavior as possible hydrogen sensor and corrosion protection. The deposition was obtained using a cyclic voltammetry technique (CV) in an aqueous solution containing 0.3 M oxalic acid and 0.1 M aniline. The PANI deposition on steel was achieved after 15 cycles, to obtain its reduced state (Emeraldine, green) and 15.5 cycles to obtain its oxidized state (Pernigraniline, blue). Hydrogen permeation tests were carried out on steel sheets by the classical Devanathan-Stachursky technique to estimate the flow of hydrogen which diffuses through the steel. For the evaluation of PANI coating as a sensor the cathodic half of permeation cell was used. This permitted to follow possible changes in color of PANI during hydrogen permeation. The PANI coating showed a great potential as hydrogen sensor, experimenting changes in color due to its variation in oxidation states due to the presence of diffused hydrogen atoms. PANI was evaluated as corrosion protector using electrochemical techniques: potentiodynamic polarization and immersion, both of them in 3.5%NaCl solution. The PANI coating protected the steel cathodically, and it had an acceptable behavior during immersion, at least in the short period of evaluation.

Keywords : Hydrogen sensor; Corrosion inhibition; PANI; Hydrogen permeation; Cyclic voltammetry.

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