Study of an alternative phosphate sealer for replacement of hexavalent chromium
By Banczek, E.P.; Terada, M.; Rodrigues, P.R.P. & Costa, I.
Published in Surface and Coatings Technology
2010
Abstract
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 CrO3 (200 mg L-1 of Cr6+) was also used for reference.