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Aluminium Bronze alloys: an alternative for pumps in marine applications



When it comes to working in an industrial, maritime environment, the challenge is to design reliable and long-lasting equipment. For a long time, steel and stainless steel have been considered the only solution despite a low corrosion resistance. Inoxyda has specialized in developing alternative solutions based on aluminium bronze alloys, which have excellent resistance to seawater corrosion but not only.

Properties of Aluminium bronze alloys developed by Inoxyda

Aluminium Bronze is a family of copper-based alloys including aluminium, nickel, and iron; each component is adjusted to improve strength, corrosion resistance, and/or machinability and is then identified by different grades according to international standards (ex: EN 1982 / ASTM /ASME):

Machined NAB alloy impeller (credit Inoxyda)

Machined NAB alloy impeller - Inoxyda

The main property comes from its protective oxide surface film, which can self-repair and is therefore a better solution in the long run, compared to any coated steel.

Biofouling resistance is another characteristic of aluminum bronze alloy, which is often ignored; unlike other standard metals, copper ions’ slow dissolution prevents organic elements from developing.

When dealing with pump applications, resistance to cavitation is an essential design criterion; cavitation results from small water vapor bubbles formed at low-pressure points, causing erosion at the point of contact, which in some extreme cases damages the blades. Nickel Aluminum Bronze provides excellent resistance to this phenomenon, explaining why NAB alloys are widely used in the shipbuilding industry, including for propellers.

All those interesting properties are further developed in the Guide to Nickel Aluminum Bronze for Engineers, published by Ivan Richardson and the Copper Development Association.

Comparison of average cavitation resistance (credit Inoxyda)

Comparison of average cavitation resistance

Learn more: Discover the full range of Inoxyda’s products for pumps and turbines

Application to pumps for seawater service

Pumps used for seawater service face severe corrosion issues for which the use of Aluminium Bronze alloys is a solution. They are available using various casting processes: sand casting, centrifugal casting, or continuous casting, thus offering opportunities to manufacture various engineered pump components such as:

Split Pump aluminium bronze (credit Inoxyda)

Split Pump aluminium bronze - Inoxyda

Inoxyda’s knowhow: a solution for seawater applications in Nordic applications

Nordic countries are historically and geographically linked to the sea; thus, the maritime industries play a significant role in the countries’ economies. Inoxyda has provided aluminium bronze castings to Scandinavia’s critical players in cooperation with Hj. Edwards & Co. AB, a Gothenburg company, focusing on engineered applications and supporting customers with world-class suppliers for more than 100 years.

Contact Edwards for more information about Inoxyda’s Aluminium Bronze Castings:

Logo Inoxyda


Benoit François

Sales Scandinavia

Hj. Edwards & Co AB
Metangatan 1P. SE-431 53, Mölndal

Tel +46 76 135 59 54