Cathodic Protection


The use of Magnesium Anodes for Cathodic Protection is a proven and effective method to protect assets from corrosion:

Here are some examples of applications of Magnesium Anodes for Cathodic Protection:

  • Magnesium Soil Anodes – Hi-Potential and H-1 (Standard Potential)
  • Magnesium Water Heater Anodes
  • Magnesium Rod
  • Magnesium Marine Anodes
Magnesium Anodes
Magnesium Soil Anodes


Magnesium Anode Production:
Galvotec’s Magnesium Anodes are produced in a variety of shapes and sizes for use in seawater, brackish water, and fresh water cathodic protection systems.
Our experience in producing galvanic anodes assures that you will receive top quality anodes that will effectively inhibit corrosion when used in a properly designed and maintained cathodic protection system.

Magnesium Anode Quality:

Strict quality measures are taken, including strategic choice of raw materials and continual quality control throughout the entire manufacturing process, resulting in the best performance of any magnesium anodes on the market

ASTM G97 Testing
ASTM G97 Testing

ASTM G97 Testing – Quality Assurance and Quality Control

Quality of High Potential Magnesium Anodes cannot be insured by Chemical Analysis alone. Performance Testing for anode closed circuit potential, open circuit potential, and anode mass loss to determine anode current capacity and efficiency is performed in a proper laboratory environment. Select control material is used per test batch

The only true and tested method of Quality Assurance of High Potential Magnesium Anodes is by testing as per ASTM G97

Galvotec’ Laboratory is one of very few laboratories in the world that is accredited to ISO Standard 17025:2015 to perform Testing in accordance to ASTM G97


The method of choice for the Chemical Analysis of Magnesium Anodes is Optical Emission Spectroscopy. The choice of certified, traceable primary standards for proper calibration is critical when utilizing this technique.

OES Spectrometer

Magnesium Anode Testing and Quality Control – Galvotec operates an A2LA  (ISO17025:2005) Accredited Laboratory for testing magnesium anodes and magnesium products. Optical Emission Spectrographic (OES) Analysis is utilized for assurance of chemical composition and ASTM G-97 is utilized for verification of electro-chemical properties.

Further technical details about anode testing are available at:

 Galvotec’s  Marine Magnesium Anodes conform in composition to the requirements of U.S. Government Specification MIL-A-21412A (Ships).  This 6% aluminum, 3% zinc alloy (AZ-63) usually provides the best combination of economy and operating characteristics in seawater or brackish water.

High Potential Magnesium Soil Anodes conform to ASTM B843 Designation Grade M1C.

Standard Potential Magnesium Soil Anodes conform to ASTM B843 Designations Grade: AZ63B(H1A), AZ63C(H1B), and AZ63D(H1C).

Galvanic Efficiency: For Marine Sacrificial Magnesium Anodes:
The current efficiency of Galvotec’s Magnesium Anodes is nominally 55% in seawater and the current capacity is about 550 amp-hr/lb.  The open circuit potential of the magnesium alloy used is nominally -1.55 volts to a copper/copper sulfate half cell in seawater; the driving voltage to galvanized steel is about 0.70 volts, providing a relatively high current
output per anode.  Both hull and condenser anodes are available with a plastisol (polyvinyl chloride) coating which serves as an excellent current barrier shield.
HiPotential Magnesium Anode Quality
hi potential magnesium anode quality

Galvanic Efficiency for Magnesium Hi-Potential Soil Anodes:

The current efficiency  Galvotec Magnesium Hi-Potential (soil) Anodes is normally equal to or greater than 50% with current capacity of at least 500 amp-hr/lb or greater. Open Circuit potentials are normally equal to or more negative than -1.70 volts when referenced to copper/copper sulfate electrode.


The Standard Potential or AZ63 (H1) Series Anodes will typically produce open circuit potentials of -1.53 to -1.55 volts when referenced to copper/copper sulfate electrode. Typical anode current efficiency will be greater than 50% and current capacity will be greater than 500 amp-hr/lb or greater.

Back-fill – Lead Wire – Packaging
Typical back-fill used for soil anodes consist of 75% gypsum, 20% bentonite and 5% sodium sulfate. Typical lead wire would be 10 ft. of #12 THHN solid. Anodes can also be supplied bare, with or without lead wire as well as customized back-fill and packaging

Magnesium 17 lb anode
17 lb high potential magnesium anode
Packaged Magnesium Soil Anode
Packaged Magnesium Soil Anode


Magnesium Anodes are effective and economical corrosion fighters that for over 25 years have been protecting a variety of steel structures in salt, brackish and fresh water, including:
    Hulls of ships, barges, tugs and boats
    Ballast tanks of ore carriers and similar vessels
    Water storage tanks
    Piers and pilings
    Heat ex changers
    Traveling screens