Corrosion inhibition of iron in 0.5 mol L-1 H2SO4 by halide ions

• Autor(a) principal: Jeyaprabha,C.
• Data de Publicação: 2006
• Outros Autores: Sathiyanarayanan,S., Muralidharan,S., Venkatachari,G.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532006000100009
• topic: corrosion inhibition; iron; sulphuric acid; halide ions

The inhibition effect of halide ions such as iodide, bromide and chloride ions on the corrosion of iron in 0.5 mol L-1 H2SO4 and the adsorption behaviour of these ions on the electrode surface have been studied by polarization and impedance methods. It has been found that the inhibition of nearly 90% has been observed for iodide ions at 2.5 <FONT FACE=Symbol>´</FONT> 10-3 mol L-1, for bromide ions at 10 <FONT FACE=Symbol>´</FONT> 10-3 mol L-1 and 80% for chloride ions at 2.5 <FONT FACE=Symbol>´</FONT> 10-3 mol L-1. The inhibition effect is increased with increase of halide ions concentration in the case of I- and Br- ions, whereas it has decreased in the case of Cl- ion at concentrations higher than 5 <FONT FACE=Symbol>´</FONT> 10-3 mol L-1. The double layer capacitance values have decreased considerably in the presence of halide ions which indicate that these anions are adsorbed on iron at the corrosion potential.