Sacrificial Anodes - ALUMINUM

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HULL AND SPECIAL APPLICATION CAST ALUMINUM ANODES

Economical Marine Vessel Protection
In saltwater environments, where electrical resistivities are usually quite low, aluminum anodes are the most economical choice for corrosion protection. These anodes offer higher current efficiency and lower anode consumption than both magnesium and zinc in aqueous saline areas, making aluminum ideal for the protection of ship hulls on oceangoing vessels. Corrpro casts an entire line of hull anodes made to two alloying standards. Alloy I produces an open circuit potential of 1.05 volts (with respect to an Ag/AgCl reference cell), and realizes a 95% current efficiency. Alloy II generates a voltage potential of 1.10, and has a lower current efficiency rating of 87% in free-flowing water. This anode material also performs better in saline mud and lower-chloride water. Because Alloy II has a more powerful driving voltage, fewer anodes are necessary to protect a given structure when elongated shapes are employed.

Both hull anodes are cast with steel core brackets for bolt or weld mounting. They are molded with tapered ends to minimize water turbulence. To ensure quality, each production run of these anodes is inspected for correct chemical composition through a variety of tests. Electrochemical tests are also employed to verify performance characteristics.

Typical Applications
Corrpro hull anodes are manufactured for the hulls of oceangoing vessels. They are also applicable for use on any other saltwater structure. Because Alloy I contains nominal amounts of mercury, it is not recommended for areas where water flow is restricted. Alloy II, which contains small amounts of indium, silicon, and zinc, is especially effective in saline mud and lower chloride water. This alloy is also the recommended protective material for produced water and treatment tanks.

Chemical Composition
Element	Content %
	Alloy I	Alloy II
Zn	0.35-0.50	2.8-3.5
Si	0.14-0.21 Max.	0.08-0.2 Max.
Hg	0.035-0.048	-
In	-	0.01-0.02
Aluminum	Remainder	Remainder

Heater Treater and Vessel Cylindrical
Aluminum Anodes

For Easy Installation
Galvanic cathodic protection requires the periodic replacement of consumed anodes. In heater treaters and other production vessels, Corrpro cylindrical aluminum anodes make this replacement process a snap. These anodes are cast from a high-potential alloy, which delivers a voltage of 1.10 (with respect to an Ag/AgCl reference cell). The alloy contains nominal percentages of indium, zinc, and silicon. This, combined with the anode's unique shape, allows Corrpro's cylindrical anode to offer one of the best current outputs available. The chemical composition of this anode also has a proven track record for delivering superior protection in produced brines with elevated temperatures.

All Corrpro cylindrical anodes are cast with eyebolt, rod, or threaded steel pipe cores. A stabilizing rod attached to these cores ensures a strong mechanical bond between the core and anode. To guarantee the highest-quality anode, Corrpro also conducts atomic absorption, inductive coupled plasma, or Baird spectrovac optical emission tests on each production run of aluminum anodes.

Typical Applications
Corrpro cylindrical anodes are recommended for use in heater treaters, pressure vessels, barges, or any other type of structure requiring a compact, replaceable aluminum anode. The characteristics of the alloy make it ideal for higher temperature or lower chloride saltwater environments.

Chemical Composition
Element	Content %
Zn	2.8-3.5
Si	0.08-0.2 max
In	0.01-0.02
Al	Remainder

MARINE PIPELINE BRACELET
ALUMINUM ANODES

Long-Life Protection For Offshore Piping
Surrounded by saline mud and often operating at elevated temperatures, offshore pipelines face severely corrosive conditions. To combat these forces Corrpro offers numerous types of aluminum bracelet anodes cast to alloying standards to deliver superior protection to steel structures in saltwater or saline mud. Under these conditions the anode material can deliver a voltage ranging between 1.05-1.09 and a current capacity of 750-980 amp-hrs./lb.
Corrpro bracelet anodes are cast in two types: semi-cylindrical and multisegmented. Both types of Corrpro bracelet anodes are manufactured with welded steel cores and are coated on the pipe side of the anode with a coal tar epoxy coating to enhance performance.

Typical Applications
Corrpro bracelet anodes are designed for use on all types of pipelines found in the saltwater environments. On pipe installations where a concrete weight coat is to be employed, square ended bracelet anodes are recommended at the same thickness as the weight coat. Tapered anodes should be used on all other pipeline installations to minimize problems during installation from the lay barge.

Chemical Composition
Element	Content %
Zn	2.8-3.5
Si	0.08-0.2 max
In	0.01-0.02
Aluminum	Remainder

OFFSHORE PLATFORM CAST ALUMINUM ANODES

Powerful Protection For Massive Structures
Saltwater is a hostile environment for the submerged metal supports on offshore platforms. To defend against this corrosive setting, Corrpro offers a full line of large cast aluminum anodes that are made to two alloying standards.

Alloy I has an open circuit voltage of 1.05 (with respect to an Ag/AgCl reference cell), and delivers a current output of 1280 amp.-hrs./lb. in saltwater. Alloy II generates a higher open circuit potential of 1.10 volts and an ampacity of 1150 amp.-hrs./lb. in saltwater. The composition contains nominal additions of indium, silicon, and zinc, which help to guard against the buildup of pacifying films around the anode. This is especially important in saline muds and brackish waters. In these environments, the Alloy II anode outperforms the Alloy I anode by providing greater current output.

Both types of anodes are manufactured with steel cores made from heavyweight Schedule 80 pipe. The pipe can be supplied in a wide variety of core configurations to accommodate numerous specifications and applications.

Typical Applications
Corrpro aluminum platform anodes are designed specifically for use on offshore drilling jackets. The two alloy compositions deliver effective galvanic protection in saltwater environments. In situations where the anode will be buried in saline mud or exposed to water with lower chloride levels, the Alloy II anode will provide more current and better protection. Additionally, since Alloy I contains a slight amount of mercury, it should not be employed in restricted water-flow areas where concentrated levels of mercury can accumulate.

Chemical Composition
Element	Content %
	Alloy I	Alloy II
Zn	0.35-0.48	2.8-3.5
Si	0.14-0.21 max	0.08-0.12 max
Hg	0.035-0.048	-
In	-	0.01-0.02
Aluminum	Remainder	Remainder

PIER, PILLING, AND BALLAST TANK CAST ALUMINUM ANODES

Corrosion Control In Saltwater Environments
Aluminum anodes are used more often than any other type of galvanic material in saltwater environments due to their relatively low consumption rate of approximately 7 lbs. per amp.-year. To meet the demand for this effective anode material, Corrpro manufactures an extensive array of aluminum anodes in two different alloys. The anodes are cast in a variety of weights and configurations to address numerous installation possibilities. Steel cores cast into each anode allow for electrical connection. The cores are available in bolt-on, eyebolt, pie, rod, or weld-on configurations, and can also be provided with lead wire upon request.
Because alloy composition is so important to the performance of galvanic anodes, Corrpro performs a number of quality control tests to ensure its aluminum anodes conform to the proper alloying specifications. The firm conducts atomic absorption, inductive coupled plasma, or Baird spectrovac optical emission tests to confirm chemical composition. The results of these tests are obtained using traceable standards developed by the National Institute of Standards and Technology.

Typical Applications
Aluminum anodes produced by Corrpro are designed for superior performance in saltwater environments. The first alloy, which has an open circuit potential of 1.05 volts (with respect to an Ag/AgCl reference cell), contains a nominal amount of mercury, and is recommended for use only in free-flowing saltwater environments. The second anode has an open circuit potential of 1.10 volts, and produces a higher ampacity and better performance than the previous alloy in lower chloride water and saline mud electrolytes.

Chemical Composition
Element	Content %
	Alloy 1	Alloy 2
Zn	0.35-0.50	2.8-3.5
Si	0.14-0.21 max	0.08-0.20 max
Hg	0.035-0.048	-
In	-	0.01-0.02
Aluminum	Remainder	Remainder

 

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