Study of an alternative phosphate sealer for replacement of hexavalent chromium


Autoria(s): BANCZEK, E. P.; TERADA, M.; RODRIGUES, P. R. P.; COSTA, I.
Contribuinte(s)

UNIVERSIDADE DE SÃO PAULO

Data(s)

18/10/2012

18/10/2012

2010

Resumo

This study evaluates the possibility of replacing the hexavalent chromium passivation treatment used as a sealer after phosphating of carbon steel (SAE 1010) by a treatment with niobium ammonium oxalate (Ox). Samples of carbon steel (SAE 1010) after being phosphated in a zinc phosphate bath (PZn + Ni) were immersed in solution of niobium ammonium oxalate (250 mg L(-1) of Nb) either at pH 3.0 or pH 8.0. A passivation treatment with a solution with CrO(3) (200 mg L(-1) of Cr(6+)) was also used for reference. The corrosion resistance of the phosphated samples after passivation treatments was analyzed in a NaCl 0.5 mol L(-1) solution using electrochemical impedance spectroscopy (EIS) and anodic polarization curves. Salt spray tests were also performed to evaluate their corrosion resistance. The results showed that the highest corrosion resistance was obtained by passivation in a solution with (250 mg L(-1) of Nb) at pH 8.0. (C) 2010 Elsevier B.V. All rights reserved.

Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)[142983/2005-5]

Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[Proc. 2007/51363-5]

Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[2008/54836-4]

Identificador

SURFACE & COATINGS TECHNOLOGY, v.205, n.7, p.2503-2510, 2010

0257-8972

http://producao.usp.br/handle/BDPI/18779

10.1016/j.surfcoat.2010.09.053

http://dx.doi.org/10.1016/j.surfcoat.2010.09.053

Idioma(s)

eng

Publicador

ELSEVIER SCIENCE SA

Relação

Surface & Coatings Technology

Direitos

restrictedAccess

Copyright ELSEVIER SCIENCE SA

Palavras-Chave #Hexavalent chromium #Coating #Niobium ammonium oxalate #AZ91D MAGNESIUM ALLOY #STEEL #COATINGS #LAYERS #Materials Science, Coatings & Films #Physics, Applied
Tipo

article

original article

publishedVersion