C-Gard™ & C-Sentry™ – Sacrificial Anodes Protecting Against Corrosion

Anode Alloys

Aluminium Alloys

The key to the manufacture of high performance aluminium alloy anodes is to manufacture them from high purity aluminium. Impalloy Limited where ever possible manufactures from low Iron (<0.6%) primary aluminium and does not routinely resuse any scrap. In this way we can provide closely controlled alloys.

DBV have performed the long term Electrochemical Capacity test to DNV RP B401, and report a result of 2580 Ahr/Kg. Our certificate is available to download.

 Element Impalloy III Impalloy III-S Impalloy III-CW
Min % Max % Min % Max % Min % Max %
Zinc 2.8 6.5 3 5.5 4.75 5.75
Indium 0.01 0.02 0.016 0.04 0.016 0.02
Silicon 0.12 0.1 0.08 0.12
Iron 0.12 0.09 0.06
Copper 0.006 0.005 0.003
Cadmium 0.002 0.002 0.002
Titanium 0.025 0.02 0.02
Others each 0.02 0.02 0.02
others total 0.05 0.05 0.05
Aluminium remainder remainder remainder

Impalloy III is a general purpose alloy used for relatively short life anodes such as ships hulls and tanks.

Impalloy III-s has become widely accepted for use in applications requiring long life such as offshore pipelines, sub-sea structures and marine terminals. This alloy generally conforms to that specified in ISO 15589-2 and NORSOK M-503

Impalloy III-CW is commonly specified by some Oil & Gas Operators for use in deepwater applications.

We can also manufacture to clients specifications.

Download the Anode Alloy Leaflet

Impalloy Zinc alloys

 Element US Mil A-18001K ASTM B418 Type I ASTM B418 Type II
Min % Max % Min % Max %
Aluminium 0.1 0.5 0.005
Cadmium 0.025 0.07 0.003
Iron 0.005 0.0014
Lead 0.006 0.003
Copper 0.005 0.002
others total 0.1
Zinc remainder remainder

US MIL A-18001K is the internationally accepted and preferred alloy for general use in sea water, brackish waters and other saline solutions. It may also be used in low resistivity, salt laden sediments and soils.

The ASTM type II alloy is more appropriately used for anodes in potable water.