Accession Number : ADA304779

Title :   The Impact of Microbiologically Influenced Corrosion on Protective Polymer Coatings.

Descriptive Note : Technical rept. 1 Oct 94-30 Sep 95,

Corporate Author : UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES DEPT OF MATERIALS SCIENCE AND E NGINEERING

Personal Author(s) : Mansfeld, F. ; Xiao, H. ; Han, L. T. ; Lee, C. C. ; Jones-Meehan, J.

PDF Url : ADA304779

Report Date : DEC 1995

Pagination or Media Count : 36

Abstract : Thirteen sets of polymer coated steel were exposed to Pacific ocean water at Port Hueneme. CA (NS) and artificial (AS) sea water in July 1994. The same types of coating systems were exposed in Key West, FL in May 1995. In this report data for three sets of coatings systems exposed at Port Hueneme and in the laboratory are discussed. Each set had a different primer - metallic zinc. IVD-Al or phosphate. Within each set one group of samples had an epoxy coating, the other group had an additional layer of polyurethane as a topcoat. Degradation of the protective properties of the polymer coatings was followed by recording impedance spectra and electrochemical potential and current noise data as well as by visual observation. Impedance data were collected at the remote test site once a week and noise data twice a week via modem from the laboratory at USC. Preliminary statistical analyses concerning the effects of the nature of the primer, presence of a topcoat and exposure medium (biotic vs. abiotic) were performed based on the breakpoint frequency obtained from impedance data and the noise resistance and the spectral noise resistance R(sn) obtained from noise data. Samples exposed to three different colonies of microorganisms containing sulfate reducing-bacteria (SRB) and a control solution were evaluated using electrochemical impedance spectroscopy (EIS). Selected samples were examined by environmental scanning electron microscopy (ESEM) to determine biofilm distribution and spatial relationships between coating damage and microorganisms. (MM)

Descriptors :   *CORROSION INHIBITION, *STEEL, *PROTECTIVE COATINGS, SPATIAL DISTRIBUTION, SCANNING ELECTRON MICROSCOPES, DEGRADATION, POLYMERS, ELECTROCHEMISTRY, PRIMERS, ZINC, PACIFIC OCEAN, POLYURETHANE RESINS, MICROORGANISMS, PHOSPHATES, SEA WATER CORROSION, EPOXY COATINGS.

Subject Categories : Coatings, Colorants and Finishes
      Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE