How we can service the marine industry
Seawater is corrosive to most construction materials; therefore specific metals are required. Copper and copper alloys are well suited to this job due to their corrosion resistance and mechanical strength. Copper-nickel alloys and aluminium bronzes are often preferred in seawater environments, used in heat exchangers/condensers, seawater piping, bearings, fasteners, propellers, shafts and offshore platform construction. Copper nickel alloys specifically have high resistance to chloride pitting, crevice corrosion and stress corrosion cracking. The addition of tin is used where bearing performance or high strength properties are required, such as stems, bushings and bearings. Copper-nickel-aluminium alloys are used for good anti-galling properties and resistance to hydrogen embrittlement. Bronzes are used due to their superior resistance to ammonia stress corrosion. In general the higher the tin content the higher the corrosion resistance. Aluminium bronzes are widely used as they combine high strength and corrosion resistance, used either in wrought or cast forms as pumps, valves, propellers, bushes, bearings, shafts and fasteners. The addition of nickel to these alloys provides increased ductility and improved castability, they have excellent resistance to cavitation and are often used for ship propellers. Silicon bronzes are used for screws, nuts, bolts, washers and pins in marine environments. Brasses are also used due to their high tensile strength for applications such as propellers and shackles. However, they can become subject to dezincification; a form of selective phase corrosion which can occur in seawater. This is generally avoided by alloying or cathodic protection.
Metal powders such as spherical copper powder (sometimes alloyed with nickel) can be used, when mixed with resin, as a deterrent to marine growth on both boats hulls and underwater structures such as pipelines.