SEDL / STP / STP970-EB / STP26012S

The Effect of Dissolved Copper on the Erosion-Corrosion of Copper Alloys in Flowing ASTM Seawater

Cheung, WK
Higher scientific officer and principal scientific officer, Division of Materials Applications, National Physical Laboratory, Teddington, Middlesex

Thomas, JGN
Higher scientific officer and principal scientific officer, Division of Materials Applications, National Physical Laboratory, Teddington, Middlesex

Pages: 15    Published: Jan 1988

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Abstract

Erosion-corrosion experiments have been carried out on tubular copper alloys in ASTM artificial seawater, using two recirculating flow systems. The results showed that the order of resistance to erosion-corrosion of the alloys was correct, but the values of the critical breakaway flow velocities were considerably greater than those reported for once-through seawater cooling systems in practice. Analysis of the recirculating seawater showed that because of the high initial corrosion rates of the copper alloys, the concentration of dissolved metal ions increased rapidly to significant values, and supersaturation of copper ions was occurring. A technique has now been developed to remove dissolved copper and other heavy metal ions from the recirculating seawater in the flow systems by passage through a suitably prepared chelating ion-exchange resin. Under these conditions, the corrosion rates of tubes of 90/10 copper-nickel were considerably higher than those obtained previously in the presence of dissolved copper ions.