Page 83 - Copper and Bronze in Art: Corrosion, Colorants, Getty Museum Conservation, By David Scott

TABLE 1.7 TYPICAL MARINE ENVIRONMENTS

MARINE ZONE ENVIRONMENT CHARACTERISTIC
BEHAVIOR OF COPPER

Atmospheric Small sea-salt particles carried by wind. Partially sheltered surfaces may deteriorate
Corrosivity varies with height above more rapidly than those exposed; top surfaces
water, dew cycle, bird droppings, may be washed free of salt by rain.
wind, etc.
Splash Wet, well-aerated surface; no fouling. Most aggressive zone for many metals and for
protective coatings.
Tidal Marine fouling present to high water. Copper may act cathodically at tidal zone.
Shallow water Seawater saturated with oxygen; pol­ Corrosion may be more rapid than in exposed
lution, sediment, and fouling may all marine zone areas; a layer of hard shell and
be present. biofouling may restrict corrosion.
Continental shelf No plant fouling; some decrease in Copper alloys may be well preserved.
oxygen, especially in the Pacific, and
at lower temperatures.
Deep ocean Oxygen varies, lower here than at sur­ Data for copper alloys sparse, but corrosion
face; temperature near o °C; velocity is limited.
and pH both lower than at surface.
Mud Sulfate-reducing bacteria present; bottom Partially buried bronzes corroded most; sub­
sediments vary in origin, characteris­ merged copper alloys may be severely attacked.
tics, and corrosion behavior.

After Schumacher 1979.

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