| Titre : |
The case of the spotty disbondment |
| Type de document : |
texte imprimé |
| Année de publication : |
2017 |
| Article en page(s) : |
p. 14-19 |
| Langues : |
Américain (ame) |
| Catégories : |
Analyse des défaillances (fiabilité)
Décollement cathodique (revêtement)
Epoxydes
Expertises
Haut extrait sec
Métaux -- Revêtements protecteurs
Réservoirs (récipients)
Réservoirs (récipients) -- revêtements protecteurs
Revêtements -- Défauts:Peinture -- Défauts
|
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
The author examined a tank of the floating-roof some 100 feet in diameter and hidden a mile off a two-lane blacktop. It was a vivid white storage tank and showed bright in stark and gleaming contrast to the head-high, green corn and golden silk of the ears.
The facility was spotless and cleaned and the tank was vented.
The tank interior was pristine but for the various areas of peeling and otherwise distressed paint.
The tank was designed to store wastewater mixed with petroleum byproducts. The exact contents were not revealed but it was a unique blend and no one knew quite how the material would interact with the coating system.
It was reported that the epoxy coating system had been installed six years earlier and purported to be high-solids (greater than 98 percent) applied at approximately 20 mils. There were discrepancies as to whether a primer was used during the initial install and whether or not repairs had taken place during the application. One account indicated that during the initial application some large areas on the floor were too thin and the material was re-sprayed. |
| Note de contenu : |
- Signs of trouble
- The visual inspection
- Getting up close and personal
- Surface prep
- Solving in the mystery
- Do you know ?
- The awner(s)
- Problem number one, two and three
- Recommendations
Fig. 1. The epoxy is clearly peeling away from the substrate. All figures courtesy of the author unless otherwise noted
Fig. 2. The scalloped area highlighted by the blue area shows evidence of good adhesion
Fig. 3. In some areas of the tank floor, the chips of coating coming off were dirty on the bottom side
Fig. 4. In some areas of the tank floor, the chips of coating coming off were clean on the bottom side
Fig. 5. Stills from a video that show areas of disbondment and poor adhesion found sporadically throughout the tank
Fig. 6. The football-shaped, damaged sections exhibiting a cohesive failure were only found in areas such as lap welds, the sump lip and slightly raised sections of the tank floor
Fig. 7. Stills from a second video show the disbonded coating coming off where the back side of the coating appears to be contaminated with dirt, or more likely, with dust from blasting
Fig. 8. The steel substrate in the failing areas examined had a peened, crater-like profile (left) and not an angular one as was required (right) |
| En ligne : |
http://www.paintsquare.com/archive/index.cfm?fuseaction=view&articleid=6105 |
| Format de la ressource électronique : |
Web |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=29162 |
in JOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL) > Vol. 34, N° 8 (08/2017) . - p. 14-19
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The case of the spotty disbondment in JOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL), Vol. 34, N° 8 (08/2017)
