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Cathodic delaminations of poly(phenyl ether ether ketone) (PEEK) coatings overlaid on zinc phosphate-deposited steels

Journal Article · · Journal of Applied Polymer Science; (United States)
;  [1]
  1. Brookhaven National Lab., Upton, NY (United States). Dept. of Applied Science

The melt-crystallized poly(phenyl) ether ether ketone (PEEK) polymer was overlaid on crystalline zinc phosphate (Zn [center dot] Ph) conversion coating-deposited and nondeposited cold-rolled steels at 400 C in air or in N[sub 2] environments. The ability of these coatings systems to protect the steel against corrosion was evaluated from the rate of cathodic delamination of the coating layer from the steel. Because the cathodic reaction, H[sub 2]O + 1/20[sub 2] + 2e[sup [minus]] = 20H[sup [minus]], at the corrosion side of a defect in the coating layer creates a high pH environment at the interfacial boundary between the coating and steel, the magnitude of susceptibility of the interfacial intermediate layers to the alkali-induced degradation played a key role in suppressing cathodic failure. The lowest level was observed in the N[sub 2]-induced PEEK/Zn [center dot] Ph/steel joint systems, thereby decreasing the rate of delamination. By contrast, oxidized PEEK induced by air in same joint systems was susceptible to the alkali-catalyzed hydrolysis. This phenomenon significantly promoted the alkali dissolution of Zn [center dot] Ph crystals, reflecting a high rate of delamination. Nevertheless, the introduction of Zn [center dot] Ph as interfacial tailoring material into the intermediate layers markedly acted in reducing the cathodic delamination of PEEK/steel joint systems.

DOE Contract Number:
AC02-76CH00016
OSTI ID:
5652786
Journal Information:
Journal of Applied Polymer Science; (United States), Journal Name: Journal of Applied Polymer Science; (United States) Vol. 50:10; ISSN 0021-8995; ISSN JAPNAB
Country of Publication:
United States
Language:
English