VIEIRA SEGUNDO, J. E. D.; http://lattes.cnpq.br/1388540284365683; VIEIRA SEGUNDO, José Etimógenes Duarte.
Resumo:
In this work, electrochemical permeation technique was applied to alloy API 5L
X80 coated with nickel or palladium on the sample detection surface in three different
thickness: 0,04; 0,08 and 0,12 um. For this, a two-compartment cell was used, both
filled with 0,1 M NaOH, separated only by the metallic membrane, acting as working
electrode. The metallic coating characterization was performed by cyclic voltammetry
technique before and after the permeation step. Results obtained showed that alloy
surface with Ni and Pd layers became more active after hydrogen permeation.
Permeation results were expressed by following properties: diffusion coefficient,
permeability and solubility. The average diffusion coefficient for samples with nickel
deposit was (2,92 ± 1,06) m2/s, while for the samples with palladium deposit was
(2,46 ± 0,61) m2/s. It was noticed that palladium shows a better electro catalytic
performance besides more reproducible measurements and minor standard
deviation. Interaction properties showed no dependence of coating thickness.
Regarding nickel, these properties presented larger fluctuation and denoted some
dependence for layer metallic coating.