Mild Steel Corrosion Inhibition, in 4 N Sulphuric Acid, by a Green Inhibitor

• Autor(a) principal: Srivastava,Mahima
• Data de Publicação: 2020
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://scielo.pt/scielo.php?script=sci_arttext&pid=S0872-19042020000200003
• topic: Amaranthus extract; sulphuric acid; mild steel; polarization; SEM; corrosion; inhibitor

Use of Amaranthus extract, as mild steel corrosion inhibitor, in a pickling paste with H2SO4, has been investigated. The electrochemical experiments were conducted to bring forth results regarding various parameters, viz., corrosion current, anodic polarization and cathodic polarization. The corrosion current gradually decreased with time, for both uninhibited and inhibited systems. Polarization curves values indicate that Amaranthus extract adsorption modified anodic dissolution mechanism, as well as cathodic hydrogen evolution. From the results, it is clear that both cathodic and anodic reactions were inhibited, and that inhibition increased as the inhibitor concentration increased in acidic media, but the cathode was more polarized. This result indicated that Amaranthus extract can be classified as a cathodic inhibitor, in a 4 N H2SO4 solution. Surface analysis via scanning electron microscope (SEM) showed a significant improvement on the mild steel plate surface morphology, in the presence of optimum inhibitor concentrations. Thus, by conducting these experiments, our aim is to use inhibited pickling acid in the paste form, so that it can be conveniently applied on large structures, as well as on small tools, to be pickled/cleaned. As a contribution to the current interest on environmentally friendly green corrosion inhibitors, the present study investigates the inhibiting effect of Amaranthus extract, a green inhibitor which is commonly known as Pigweed.