Título

EFEITO DA CONCENTRAÇÃO DE CLORETO NA CORROSÃO SELETIVA DE LIGAS CUPRONÍQUEL 90-10 (Cu10Ni) COM ADIÇÕES DE FERRO E ALUMÍNIO

EFFECT OF THE CHLORIDE CONCENTRATION ON THE SELECTIVE CORROSION OF 90-10 CUPRONICKEL ALLOYS (Cu10Ni) WITH IRON AND ALUMINUM

Autoria

Liberto, Rodrigo César Nascimento; Magnabosco, Rodrigo; Alonso-Falleiros, Neusa

DOI

10.5151/2594-5327-0034

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Resumo

O presente trabalho tem o objetivo de avaliar a resistência à corrosão seletiva de níquel (desniquelação) da liga cuproníquel 90-10 (Cu10Ni), com adições de ferro e alumínio, através de ensaios de polarização potenciodinâmica cíclica em soluções aquosas de 0,01M, 0,1M e 0,6M NaCl. As ligas Cu10Ni, Cu10Ni-1Al, Cu10Ni-3Al, Cu10Ni-1,3Fe e Cu10Ni-3Al-1,3Fe foram fundidas em forno poço, solubilizadas a 900oC por 3 horas, laminadas a frio com 87,5% de redução e novamente solubilizadas a 900oC por 1 hora. Os ensaios de polarização em NaCl, foram realizados sob superfície com acabamento polido (1

 

This work evaluated the resistance to selective corrosion of nickel (denickelification) of the 90-10 curponickel alloys (Cu10Ni), with additions of iron and aluminum,through potenciodynamic polarization tests in aqueous solutions of 0,01M, 0,1M e0,6M NaCl. The alloys Cu10Ni, Cu10Ni-1Al, Cu10Ni-3Al, Cu10Ni-1,3Fe and Cu10Ni-3Al-1,3Fe had been casting and solution treated, and after that cold rolled andannealed. The polarization tests had been carried over polished surfaces, begginingafter 5 minutes of imersion, and 300 mV below of the corrosion potential. The scanrate was the 1 mV/s, with scanning reversal at a current density of approximately 10-32A/cm . The results showed that all alloys presented a passivity break potential, which characterizes the beginning of the selective corrosion process. The most resistant alloys to the beginning of this process were more attacked, with the highest localized losses of nickel. In the 0,01M and 0,1M NaCl solutions the corrosion process was more localized. The results showed that the alloys most resistant to the beginning of the denickelification process suffered more intense denickelification.

Palavras-chave

Liga cuproníquel; Corrosão seletiva; Ensaios eletroquímicos; Cloreto.

Cupronickel alloys; Selective corrosion; Electrochemical tests; Chloride.