D-shaped Bare Magnesium Anode

Magnesium anodes are a widely used solution for corrosion control when impressed current cathodic protection is not an appropriate or feasible option for the intended facilities.

Bare magnesium anodes are most commonly used anode for applications in soil. The greater negative potential of the magnesium anode results in a high driving voltage which allows the anode to supply sufficient protection to underground steel structure in soil with medium to high resistivity (1,000 – 10,000 Ω·cm).

Our bare magnesium anode is usually made into two types with differing electrode potential (relative to Cu/CuSO4 reference electrode). They can be used to protect most buried metallic structures found in a range of soil resistivities. High potential magnesium anode are often utilized in dry or resistant earth, or where increased current is needed due to a poorly coated tank. Standard potential magnesium anodes perform well in corrosive soil, if the tank is well coated, and in this case will last longer than the high potential alloy.


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Quality Substrate Material

Our magnesium anode is manufactured under the ASTM B843-M1C standard for high potential or ASTM B843-AZ63B standard for standard potential, according to the following composition:

Element High Potential (ASTM B843 – M1C) Standard Potential (ASTM B843 – AZ63B)
Aluminum (Al) 0.01% 5.3 – 6.7%
Manganese (Mn) 0.5 – 1.3% 0.15 – 0.7%
Zinc (Zn) 2.5 – 3.5%
Silicon (Si) 0.05% 0.1%
Copper (Cu) 0.02% 0.02%
Nickel (Ni) 0.001% 0.002%
Iron (Fe) 0.03% 0.003%
Other Each 0.05%
Others Total 0.3% 0.3%
Magnesium (Mg) Remainder Remainder

Different Electro-potential Options

There are two common cast magnesium anode available:
1. Standard Magnesium Alloy Anode

A standard potential anode has a nominal corrosion potential of -1.55 volts (relative to a Cu/CuSO4 reference electrode). It is ideal for soil conditions where resistivity is under 20 Ω·cm.

2. High Potential Magnesium Alloy Anode

High potential magnesium anodes have higher open circuit voltage and driving potential. It produces an open circuit potential of negative 1.7~1.75 volts, which is 20~30% greater than is typically found with conventional magnesium anodes. This yields more current output and achieves a greater efficiency; reaching a sufficient cathodic protection level whilst maintaining a lower consumption of the anodes. They are ideally suited for structures buried in soils with resistivities exceeding 2,000 Ω·cm, or for structures containing numerous corrosion clusters.

Technical Measurement High Potential Standard Potential
Open Circuit Potential (-V) 1.7 – 1.75 1.5 – 1.55
Close Circuit Potential (-V) 1.7 – 1.75 1.7 – 1.75
Min. Current Capacity 500A.h/lbs (1100A.h/kg) 550A.h/lbs (1230A.h/kg)
Min. Current Efficiency 50% 55%

Remarks: Open/close circuit potential is with respect to a Saturated Calomel Reference Electrode.

Measured Electrical Efficiency Curve of Bare Magnesium Anode

Strict Quality Control

By conforming to ISO 9001:2015 standards, our anodes are manufactured, inspected, and tested in accordance with the most stringent quality control procedures to ensure peak performance.

Customized Configurations

Standard sizes below are available at Jennings Anodes warehouse. Other sizes are available upon request.

Model Weight High Potential Standard Potential
Length Width Height Length Width Height
JA – MG – 5D2 5 lbs (2.3 kg) 7.5″ (190mm) 3.5″ (89mm) 3.7″ (95mm) 12″ (305mm) 3.5″ (89mm) 3.7″ (95mm)
JA – MG – 9D3 9 lbs (4.1 kg) 13.6″ (345mm) 3.5″ (89mm) 3.7″ (95mm) 12.8″ (325mm) 3.5″ (89mm) 3.7″ (95mm)
JA – MG – 17D3 17 lbs (7.7 kg) 25.25″ (645mm) 3.5″ (89mm) 3.7″ (95mm) 24″ (610mm) 2.5″ (63.5mm) 2.6″ (67mm)
JA – MG – 20D2 20 lbs (9.1 kg) 60″ (1250mm) 2.75″ (70mm) 3.0″ (76mm) 58.5″ (1485mm) 2.75″ (70mm) 3.0″ (76mm)
JA – MG – 32D5 32 lbs (14.5 kg) 19.6″ (498mm) 5.5″ (140mm) 5.7″ (146mm) 18.6″ (472mm) 5.5″ (140mm) 5.7″ (146mm)
JA – MG – 48D5 48 lbs (21.8 kg) 29.5″ (750mm) 5.5″ (140mm) 5.7″ (146mm) 28.0″ (710mm) 5.5″ (140mm) 5.7″ (146mm)
JA – MG – 60D4 60 lbs (27.3 kg) 60.0″ (1524mm) 4.4″ (112mm) 4.4″ (112mm) 58.5″ (1485mm) 4.4″ (112mm) 4.4” (112mm)

Main Technical Parameters






Fine Sand, Soil


Pipelines, Storage Tank