Study of conversion coatings obtained from tungstate-phosphoric acid solutions

被引：33

作者：

da Silva, CG

Correia, AN

de Lima-Neto, P

Margarit, ICP

Mattos, OR

机构：

[1] Univ Fed Ceara, Dept Quim Anali & Fis Quim, BR-60455970 Fortaleza, Ceara, Brazil

[2] Univ Fed Rio de Janeiro, Dept Proc Inorgan, Esc Quim, Rio De Janeiro, Brazil

[3] Univ Fed Rio de Janeiro, PEMM, COOPE, Esc Politecn, Rio De Janeiro, Brazil

来源：

CORROSION SCIENCE | 2005年 / 47卷 / 03期

关键词：

tungstate; conversion coatings; coatings; EIS;

D O I：

10.1016/j.corsci.2004.07.008

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Conversion coatings on zinc surfaces (Zn and electrogalvanized steel) were obtained with tungstate baths acidified by phosphoric acid under different experimental conditions. Open circuit potential and local pHs were monitored during the conversion processes. The conversion layers were submitted to immersion tests monitored by open circuit potential and electrochemical impedance spectroscopy. Scanning electron microscopy and energy dispersive X-ray complemented the electrochemical measures. The local pH measurements have evidenced that the conversing process occurs at a specific value of pH. Electrochemical impedance has detected similarities between the deterioration process of tungstate and chromate conversed zinc surfaces. (C) 2004 Elsevier Ltd. All rights reserved.

引用

页码：709 / 722

页数：14

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