The addition of nickel to copper improves strength and corrosion resistance without reducing the good ductility. Due to copper-nickel alloys'  excellent resistance to seawater corrosion,  ease of fabrication and high inherent low susceptibility to the attachment of marine organisms. They have provided reliable service for several decades whilst offering effective solutions to today’s technological challenges.

The two main alloys are 90/10 (90% copper, 10% nickel) and 70/30 (70% copper, 30% nickel). The 70/30 is the stronger and has greater resistance to seawater flow, but the 90/10 will provide good service for most applications and, being less expensive, tends to be more widely used. Nexteck, for instance, also provide this kind copper nickel alloy which is referred to as CuNi10. Both alloys contain small but important additions of iron and manganese which have been chosen to provide the best combination of resistance to flowing seawater and to overall corrosion.

Copper-nickel alloys are widely used for marine applications, such as seawater pipework, offshore fire water systems, heat exchangers and condensers, sheathing of legs and risers on offshore platforms and boat hulls, hydraulic lines, fish cages for aquaculture and desalination units.