| Titre : |
Characterization of a lacquer film formulated with phosphating reagents for corrosion protection of galvanized substrates |
| Type de document : |
texte imprimé |
| Auteurs : |
S. Feliu, Auteur ; V. Barranco, Auteur |
| Année de publication : |
2004 |
| Article en page(s) : |
p. 93-102 |
| Note générale : |
Bibliogr. |
| Langues : |
Américain (ame) |
| Catégories : |
Caractérisation
Chimie -- Essais et réactifs
Fluorures
Laque et laquage
Nitrites
Phosphatation
Revêtements protecteurs
Spectroscopie des rayons X
|
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
This paper analyzes the chemical composition of the interface resulting from the application of an organic coating (lacquer) containing phosphating reagents on galvanized steel, galvanneal, and galfan substrates and its stability after short periods of exposure to condensing humidity and UV light (UVCON test). X-ray photoelectron spectroscopy (XPS) has shown that the lacquer drying process gives rise to a number of discontinuities on the lacquer surface (pores), exposing the phosphate layer formed on the original metallic coating surface. It is interesting to note the detection of fluoride and nitrite ions and phosphoric acid not combined with zinc (perhaps as HPO42- and H2PO4-) on the lacquered surfaces before testing, which suggests a tendency of these species to concentrate on the outer surface of the phosphate layer or at the lacquer-phosphate layer interface (in zones covered by the lacquer). After one day of exposure to the UVCON test, XPS reveals the disappearance of the fluoride and nitrite ions and of the free phosphoric acid. After 15 days of exposure to the UVCON test, the carbon content is seen to have decreased considerably, while the zinc, phosphorus, and titanium contents have risen. The low atomic percentages of carbon (only moderately higher than those obtained with the coatings in bare state) and Zn/P atomic ratios close to 1.5 suggest the removal of a very substantial percentage of the lacquer, leaving the zinc phosphate formed on the surface of the different metallic coatings exposed. This quick and significant drop in the lacquer content barely seems to have a repercussion on the degradation of the metallic substrate during the UVCON test, since its visual aspect remains unaltered. |
| DOI : |
10.1007/s11998-004-0003-5 |
| En ligne : |
https://link.springer.com/content/pdf/10.1007%2Fs11998-004-0003-5.pdf |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3954 |
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 1, N° 2 (04/2004) . - p. 93-102
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