Accession Number:

ADA303998

Title:

Surface Modification, Organometallic and Polyaryl Coatings, and Flame Spray Technologies for Preventing Corrosion of Metals.

Descriptive Note:

Final rept. 15 Jul 92-31 Dec 94,

Corporate Author:

BROOKHAVEN NATIONAL LAB UPTON NY

Personal Author(s):

Report Date:

1995-05-01

Pagination or Media Count:

25.0

Abstract:

To improve adherent properties of electrogalvanized steel EGS to polymeric topcoats, the surfaces of EGS were modified by polyelectrolyte-modified zinc phosphating solution. The electrochemical reaction between phosphating solution and EGS led to the complete coverage with fully grown hopeite crystals after only 5 sec treatment, thereby improving adhesion to topcoating and providing protection of EGS against corrosion. To evaluate the ability of polyphenylene sulfide PPS coatings to protect zinc phosphate Zn.Ph-treated steels from corrosion in a wet, harsh environment, we exposed them in autoclave to attempt heating-cooling cyclic fatigue tests 1 cycle 12 hr at 200C 12 hr at 25C up to 90 times. The major chemical reaction at the interfaces between the PPS and Zn in the Zn.Ph layer during cycling led to the formation of ZnS reaction product, which enhanced the Zn.Ph-to-PPS adhesive bond correspondingly, there were no signs of peeling and separation of the coating after 90 cycles. Organometallosiloxane polymer OMSP was synthesized through the hydrolysis-condensation reaction of the mixed precursor solutions of the N-3-TRIETHOXYSILYPROPYL-4,5,-DIHYDROIMIDAZOLE AND B-trimethoxysilylethyl-2-pyridine sols in liquor medium and the metal alkoxides and metallocene dichloride dissolved in water or tetrahydrofurane. The OMSP films thickness, 0.3 to 1.0 microns deposited by simple dip-withdrawing coating methods to aluminum alloys displayed the 3000 hr-salt spray resistance. Using a flame spray coating process, the methacrylic acid-modified polyethylene copolymer was overlaid onto cold rolled steel surfaces.

Subject Categories:

  • Coatings, Colorants and Finishes
  • Properties of Metals and Alloys
  • Physical Chemistry
  • Polymer Chemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE