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Organic coatings in simulated flue gas desulfurization environments: Final report

Technical Report ·
OSTI ID:5935933

Coatings prepared from the following resin systems and applied to steel were evaluated in simulated flue gas desulfurization environments: nine combinations of epoxy resin and amine hardeners, three vinyl systems, a polyester, a fluoropolymer, a urethane/asphalt and an electrostatically sprayed, fusion-bonded epoxy. The evaluation techniques used on the coatings before and after environmental exposure included: corrosion potential, AC conductance at 2 kHz, DC resistance, weight gain and tensile adhesion. The results for the nine combinations of three epoxy resins and three hardeners exposed to 0.1M H/sub 2/SO/sub 4/, and to H/sub 2/SO/sub 4/ containing other salts and adjusted to pH 0.5, showed that the hardener had more effect on behavior than the resin; a bisphenol A and two novolac resins showed the poorest performance when hardened with a mixed aromatic/aliphatic amine, and the best performance when hardened with an aliphatic or cycloaliphatic amine. Two epoxy systems showed particularly good performance: a bisphenol A hardened with a cycloaliphatic amine and a novolac hardened with an aliphatic amine. The electrostatically applied, fusion-bonded epoxy coating showed no evidence of deterioration of the coating nor corrosion of the substrate after 5000 h exposure to 0.1M H/sub 2/SO/sub 4/. Epoxy and vinyl coatings exhibited no cracking and no corrosion in welded and non-welded areas after thermal cycling twelve times between room temperature and 100 to 120/sup 0/C followed by exposure to acid. The epoxy coatings had better impact resistance after thermal cycling than the vinyl coatings. 15 refs., 20 figs., 23 tabs.

Research Organization:
Lehigh Univ., Bethlehem, PA (USA). Center for Surface and Coatings Research; Electric Power Research Inst., Palo Alto, CA (USA)
OSTI ID:
5935933
Report Number(s):
EPRI-CS-5449; ON: TI88920047
Country of Publication:
United States
Language:
English