Admiralty Copper is a special copper alloy primarily composed of copper (Cu), zinc (Zn), and tin (Sn). A typical Admiralty Copper alloy, such as HSn70-1, contains approximately 70% copper, 29% zinc, and 1% tin.
This alloy is also known as tin brass, and the addition of tin is a key factor in its excellent seawater corrosion resistance.
Admiralty Copper exhibits excellent corrosion resistance in seawater. In marine environments, a thin, dense protective film forms on the surface of copper alloys, primarily composed of copper and tin oxides and complex salts.
This protective film effectively prevents seawater from attacking the alloy's interior, slowing the rate of corrosion. For example, compared to ordinary brass, the corrosion rate of Admiralty Copper can be several times lower when immersed in seawater for long periods of time.
In addition to Admiralty Copper, two other copper materials also exhibit strong corrosion resistance:
One is the copper-nickel alloy, also known as white copper. Copper-nickel alloys are primarily composed of copper and nickel. Common alloys include 90% copper and 10% nickel (C70600) and 70% copper and 30% nickel (C71500). The addition of nickel modifies the copper's crystal structure, allowing the alloy to form a denser passivation film. In seawater, this passivation film effectively blocks the intrusion of corrosive ions such as chloride ions.
In seawater, a protective film composed primarily of nickel oxide and copper oxide forms on the surface of copper-nickel alloys. This film exhibits excellent stability and self-healing properties. For example, if the film is partially damaged, the copper and nickel in the alloy rapidly react with the oxygen in the seawater under the action of seawater to regenerate the protective film. This alloy exhibits an extremely low corrosion rate in seawater, typically around 0.002-0.005 mm/year, far lower than that of ordinary copper.
Copper-nickel alloys are widely used in marine engineering applications, such as ship seawater cooling systems, heat exchangers, and piping systems on offshore oil platforms. Taking a ship's seawater cooling system as an example, copper-nickel alloy pipes can withstand long-term seawater erosion and corrosion, effectively ensuring the cooling efficiency of the ship's power system.
Another type of alloy is aluminum bronze.
Aluminum bronze is a copper alloy with aluminum as the primary alloying element, typically with an aluminum content between 5% and 12%. Examples include QAL9-2 aluminum bronze and QAL9-4 aluminum bronze.
Aluminum forms a hard aluminum-copper compound phase within the alloy, which is distributed within the copper matrix, enhancing the alloy's strength and hardness. Furthermore, the aluminum on the alloy's surface preferentially reacts with oxygen, forming a dense aluminum oxide protective film.
In a seawater environment, this aluminum oxide protective film protects against seawater corrosion. Even if this film is locally damaged, the aluminum in the alloy will continue to react with oxygen in the seawater to repair it. Furthermore, the copper matrix in the aluminum bronze participates in the passivation process to a certain extent, forming a complex protective film structure. Its corrosion rate is generally around 0.01-0.05 mm/year, making it one of the most resistant copper alloys to seawater corrosion. Aluminum bronze is commonly used in the manufacture of ship propellers, pump impellers, valves, and other components. For example, ship propellers rotate at high speeds in seawater, subjecting them to intense erosion and corrosion. Aluminum bronze propellers, with their excellent corrosion resistance and mechanical properties, ensure the ship's normal navigation.
The company has a cluster of leading copper processing production lines in China, including:
German imported precision copper tube production line (annual output of 30,000 tons)
Japanese technology copper foil rolling line (thinnest up to 6μm)
Fully automatic copper bar continuous extrusion line
Intelligent copper sheet and strip finishing mill unit
Digitalized control and management of the whole production process is realized through MES system, and the dimensional accuracy of the products can reach ±0.01mm.
