Corrosion Protection of Steel and Bond Durability at Polyphenylene Sulfide-to-Anhydrous Zinc Phosphate Interfaces
Abstract
To enhance the performance of high-temperature polyphenylene sulfide (PPS) coating in protecting steels from corrosion, the cold-rolled steel surfaces were prepared with anhydrous zinc phosphate (Zn . Ph) conversion coatings containing poly (acid) anhydride as an interfacial tailoring material. The factors contributing to the formation of a good bond at the PPS/Zn . Ph joints were as follows: (1) the chemical reaction of PPS with Fe203 in the Zn . Ph layers, (2) PPS-to-poly (acid) anhydride interaction, and (3) the mechanical interlocking between PPS and the rough Zn . Ph crystal surfaces. Although such interfacial bond structures provide a superior durability of PPS/Zn . Ph joints against a hot H2SO4 solution, the cathodic reaction, H2O + 1/2 O2 + 2e - = 2OH-, occurring at any defect in the PPS/Zn . Ph joint system when NaCl is present will lead to the delamination of the PPS film from the phosphated steel. This cathodic delamination was due mainly to alkali-induced dissolution of Zn . Ph layers. However, the rate of delamination for the PPS/Zn . Ph systems was considerably lower compared with that for the PPS/steel system in the absence of Zn . Ph.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1992
- Accession Number
- ADA255590
Entities
People
- N. R. Carciello
- T. Sugama
Organizations
- Brookhaven National Laboratory