Estudo da corrosão e inibição dos aços carbono AISI 1010, inoxidável AISI 316 e duplex UNS S31803 em meio de solução de íons cloreto
Nenhuma Miniatura disponível
Data
2014-01-01
Autores
Moreira, Roberta Rossi
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal do Espírito Santo
Resumo
The behavior of corrosion and corrosion inhibition of AISI 1010 carbon steel, AISI 316 stainless steel and UNS S31803 duplex steel was studied in sodium chloride solution (3.0 wt. %), in the absence and presence of benzimidazole and imidazole corrosion inhibitors. The chemical and morphological characterization of steels were performed using the techniques such as optical emission spectrometry, X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). Electrochemical analysis were performed through the techniques of potentiodynamic polarization and electrochemical impedance spectroscopy. XRD analysis showed that the AISI 1010 carbon steel was consisted by ferrite phase, and the AISI 316 stainless steel showed two distint phases, which composed of FeNi and Cr, finally the UNS S31803 duplex steel displayed austenite and ferrite phases. Additionally, metallographic and SEM and EDX analysis allowed to identify certain regions and elements present in the steel which provide corrosion occurring, such as inclusions. The inhibitors were tested at different concentrations (25 ppm, 50 ppm, 100 ppm, 500 ppm and 1000 ppm) for the three steel through the polarization curves and electrochemical impedance, and it was found that all concentrations showed an increase in corrosion resistance for steels. Polarization curves analysis showed that the benzimidazole provided to AISI 1010, AISI 316 and UNS S31803, inhibition efficiencies of about 51%, 71% and 75%, respectively. While imidazole showed an efficiency of about 73%, 95% and 86%, respectively. The electrochemical impedance results showed that the benzimidazole inhibition efficiencies were approximately 52%, 73% and 71%, respectively, for AISI 1010, AISI 316 and UNS S31803 steels. In the case of the imidazole was obtained efficiencies of about 96% for the AISI 1010 and AISI 316 steels and 85% for the UNS S31803 steel. Weight loss tests showed that for AISI 1010 steel, both benzimidazole and imidazole inhibit corrosion, and reduced the corrosion about 17% and 24%, respectively. In the analysis of the polarization curves in studies with seawater, it was observed that the inhibitors were lower efficient than in the middle chloride solution. The benzimidazole showed efficiencies of about 14%, 50% and 33% for AISI 1010, AISI 316 and UNS S31803 steels, respectively. In the case of Imidazole, it was observed that the inhibition efficiency of approximately 21%, 59% and 34% for the same steels, respectively. In all electrochemical analysis and weight loss test, imidazole proved to be the better inhibitor for the steels investigated.
Descrição
Palavras-chave
Carbon steel , Stainless steel , Chloride , Corrosion inhibitor , Benzimidazole , Imidazole
Citação
MOREIRA, Roberta Rossi. Estudo da corrosão e inibição dos aços carbono AISI 1010, inoxidável AISI 316 e duplex UNS S31803 em meio de solução de íons cloreto. 2014. 122 f. Dissertação (Mestrado em Química) - Universidade Federal do Espírito Santo, Centro de Ciências Exatas, Vitória, 2014.