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The difference Between impressed current cathodic protection system and traditional sacrificial anode
Impressed current cathodic protection (ICCP) and sacrificial anode are two mainstream electrochemical technologies for metal corrosion protection. Their fundamental difference lies in their power sources: sacrificial anode relies on the self-dissolution and consumption of more reactive metals (such as zinc and aluminum) to provide the protective current; while ICCP actively provides and precisely controls the protective current using an external power source. The former is simple and direct, at the cost of material consumption; the latter is powerful and controllable, driven by electricity. The key to choosing between them lies in balancing structural scale, environmental conditions, and total life-cycle cost.
Overview
| Sacrificial Anode(Zinc Block) | Impressed current cathodic protection (ICCP) |
| Working principle: Utilizing a more negatively charged metal (zinc, magnesium, aluminum, etc.) as the anode, a self-generated current is generated to protect the structure. | Working principle: Current is supplied by an external power source (rectifier), making the protected structure the cathode. |
| No External Power Supply is required | Need External Power Supply is required |
| A few tons or more of weight is added to the hull | The additional weight is very low |
| Due to the metal characteristics, the scope of protection is limited | Wide range of protection |
| Zinc block will be affected by passivation and quality purity protection effect, the life of zinc block is limited, generally 2 to 3 years | Titanium anode with mixed precious metal oxide coating, 15 years service life |
| The maintenance shall be carried out manually on site, and the replacement or replenishment shall be carried out by docking or underwater welding | Easy maintenance, 4~5 years for normal equipment inspection once |
| 2~3 years of consumption needs to be replaced, the cost is high | The overall use cost of a single installation is cheap |
| It cannot be automatically adjusted. Once installed, the output current is determined by environmental factors (temperature, salinity) and cannot be adjusted according to seasonal or conditional changes. | The output current can be automatically adjusted through reference electrode feedback to ensure that the protection potential is always within the optimal range and adapts to environmental changes. |
| It is necessary to check the corrosion condition manually on a regular basis | The equipment can automatically monitor the corrosion of the steel structure of pipe foundation in real time |
| Zinc blocks are consumed naturally and cannot be monitored | Remote monitoring function(optional) |
| During the use of the equipment, a large amount of Zn and Al ions are released in the seawater, destroying the ecosystem | No Pollution to the Marine environment |
Application Small or simple structures (small boats, short pipes) Low resistivity environments (such as seawater) Areas without power supply As a supplement to or temporary protection for ICCP | Application Large and complex structures (large ships, offshore platforms, long-distance pipelines) High resistivity environments (freshwater, soil) Major projects requiring long-term, stable, and precise protection. |
Currently, intelligent ICCP systems are under development, integrating automatic monitoring, remote control, and data logging functions, making cathodic protection more efficient and intelligent. Sacrificial anode materials are also being improved, with the development of more efficient and longer-lasting alloy materials. In practical applications, hybrid systems are sometimes used, combining the advantages of both.
The final selection should be based on the specific project's technical requirements, environmental conditions, economic budget, and long-term maintenance considerations. For critical infrastructure, a professional corrosion assessment and engineering analysis are generally recommended to determine the most suitable protection scheme.
