Avaliação do desempenho de hidróxidos duplos lamelares contendo benzotriazol e óxidos de nitrogênio como aditivos em primer automotivo para proteção contra corrosão
Corrosion of metals comprises its deterioration due to the interaction with environment, what presents an economic associated aspect, once that resources are spent to repair these damaged materials. Organic coatings are commonly employed for metals protection; however, these coatings confer a physic...
| Autor principal: | Pellanda, Alana Cristine |
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| Formato: | Dissertação |
| Idioma: | Português |
| Publicado em: |
Universidade Tecnológica Federal do Paraná
2019
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| Assuntos: | |
| Acesso em linha: |
http://repositorio.utfpr.edu.br/jspui/handle/1/4217 |
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| Resumo: |
Corrosion of metals comprises its deterioration due to the interaction with environment, what presents an economic associated aspect, once that resources are spent to repair these damaged materials. Organic coatings are commonly employed for metals protection; however, these coatings confer a physical protection barrier, which are prone to failures that may expose metal to the environment. Thus, insertion of particles which are capable to promote active protection against corrosion in these coatings is a relevant approach. Layered Double Hydroxides (LDH), which consists of inorganic hydrotalcite-type particles and are able to trap anions between its layers, have been studied as corrosion inhibitors anions carriers to promote active protection. These LDH show double functionality: 1) promote controlled release of corrosion inhibitors and 2) entrap corrosive anions, decreasing the medium aggressiveness. In this work, two commercial LDH containing different corrosion inhibitors (nitrogen oxides and benzotriazole) were evaluated on its ability to ion exchange and anticorrosion performance of carbon steel. Regarding to nitrogen oxide-loaded LDH, FourierTransform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD) results showed that nitrogen oxides were successfully intercalated, which were released in presence of chloride media. OCP results showed that the extract obtained from this LDH shifted OCP to nobler values, indicating the protection of metal. For benzotriazole-loaded LDH, FTIR and XRD results indicated the presence of benzotriazole in the structure, but its release was not observed. OCP results showed no significant increase of steel protection, corroborating with the conclusion that benzotriazole ions did not migrate to metal surface. Considering these results, it was proceeded the insertion of nitrogen oxides-loaded LDH in an automotive primer, under three different concentrations (0.2, 1 and 3%). Electrochemical Impedance Spectroscopy (EIS) showed that the more effective concentration on corrosion delay was 0.2%, which better balanced protection level conferred by LDH with a possible loss on effectiveness of coating due to porosity increase. |
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