Accession Number : AD0698013

Title :   CATHODIC REDUCTION OF CUPROUS OXIDE IN VINYL ANTIFOULING PAINTS,

Corporate Author : DEFENCE RESEARCH ESTABLISHMENT PACIFIC VICTORIA (BRITISH COLUMBIA)

Personal Author(s) : Anderton,W. A.

Report Date : 17 MAR 1969

Pagination or Media Count : 17

Abstract : On the cathodically protected bottoms of Canadian naval ships, when coated with a vinyl system including a cuprous oxide pigmented antifouling paint, black patches are frequently observed. It has been shown that these patches are electrically conductive and that the colour is the result of the reduction of cuprous oxide to metallic copper. This phenomenon is of practical importance because these areas transmit a relatively large cathodic current, with the possible consequence that the cathodic protection system may be unable to supply sufficient current for complete protection of the hull. The metallic copper, being cathodically protected, will not go into solution and so fouling may occur. Cathodic deposit on the conductive areas may increase the drag on the ship. A mechanism for this phenomenon is described. Experimental work has shown the conditions under which it occurs, and how it may be lessened. (Author)

Descriptors :   (*CATHODIC PROTECTION, *ANTIFOULING COATINGS), (*COPPER COMPOUNDS, *REDUCTION(CHEMISTRY)), PAINT PRIMERS, COPPER, VINYL PLASTICS, ELECTROCHEMISTRY, SHIP HULLS

Subject Categories : Coatings, Colorants and Finishes
      Fabrication Metallurgy
      Plastics
      Marine Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE