A Study to Determine the Mechanisms of Corrosion of Copper-Nickel Alloys in Sulfide-Polluted Seawater.
Abstract
The corrosion of 90:10 Cu:Ni and 70:30 Cu:Ni alloys in flowing seawater (1.62 m/s) has been studied as a function of oxygen concentration using the linear polarization, ac impedance, and potential step methods for measuring the polarization resistance. Satisfactory agreement is obtained between these three semicontinuous techniques and measurements of weight loss, thereby demonstrating the suitability of electrochemical methods for monitoring the corrosion rate of cupronickel alloys in seawater. The high-nickel alloy is found to be more corrosion resistant than the 90:10 Cu:Ni alloy under the conditions employed, provided that (O2) < or = 6.60 mg/1. In oxygen-saturated seawater, the superior behavior of the 70:30 Cu:Ni alloy is no longer observed. The loss in corrosion resistance of the 70:30 Cu:Ni alloy is correlated with a shift in the corrosion potential, to a value more noble than the 'break-away potential' (defined here as the potential at which a sudden increase in anodic current occurs on sweeping the potential in the active to noble direction).
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1978
- Accession Number
- ADA051833
Entities
People
- B. C. Syrett
- D. D. Macdonald
- S. S. Wing
Organizations
- SRI International