The prevention of marine fouling by the controlled dissolution of copper and its alloys

• Main Author: Swain, Geoffrey William John
• Format: Dissertation
• Language: English
• Published: University of Southampton 1982
• Subjects: Water pollution & oil pollution

The phenomenon of marine biological fouling is described and methods for its prevention are discussed. The use of copper as an antifouling surface is considered and an electrochemical method for improving its performance is proposed. Seawater exposure trials of freely corroding, cathodically protected and electrochemically controlled copper and copper alloy specimens are described. The results show that the antifouling performance of these metals can be improved, compared to the freely corroding situation, by the electrochemical control of their dissolution. The limiting factors for this method are the formation of cathodic chalk and /or surface passivation layers. The data has allowed the corrosion rates, surface products and electrochemistry of copper and its alloys to be related to fouling. Laboratory experiments investigated the copper output rates in relation to anodic current density. They show that, at the current densities used during the exposure trials, the copper corrodes to cuprous oxide and that the solution rate of cuprous oxide determines the corrosion rate. Cuprous oxide formation is modified by different copper alloys and this mechanism appears to be important in determining the antifouling performance of the freely corroding metals. The electrochemical method produces a more efficient use of copper surfaces for antifouling. Practical considerations of the galvanic compatibility with other materials used in the marine environment limit this method to specialised applications.