Sacrificial Anode Cathodic Protection (SACP), also known as Galvanic Anode Cathodic Protection (GACP), is a crucial method in protecting metals and structures from corrosion. By utilizing Zinc, Aluminum, or Magnesium alloys, these anodes supply electrons to the protected metal, effectively halting its corrosion and making the anode itself the sacrificial element. This popular corrosion protection solution is now widely adopted due to its cost-effectiveness, ease of installation, and ability to extend the lifespan of critical infrastructures.
This article explores the principles, benefits, and diverse applications of SACP, highlighting the science behind its effectiveness.
ESC, with its expertise and experience, is well-equipped to design, supply, install, and commission cathodic protection systems, including sacrificial anodes of various dimensions and configurations. You can trust us to provide comprehensive support for your corrosion protection needs. For inquiries, please contact us at anodes@esccorrosion.com or visit our website.
Principles and Benefits of a SACP
As a key player in the process, your understanding of how the anodes supply the protected structure or metals with electrons is crucial. This process effectively halts corrosion, making the protected Metal/Structure the cathode and the less noble material as an anode prone to corroding, thus taking the term “Sacrificial”.
Noble Metals are classified based on their chemical and physical properties such as Resistance to Corrosion, Chemical Reactivity, Electron Configuration, Electrochemical behavior, and such. In choosing the right fit to be used as a Sacrificial Anode, it is determined through Electron Configuration, where the nobility of a metal is associated with its electron configuration, specifically the d-band electrons. Where Higher Electron Configurated Metals such as Gold, Silver, and Platinum are filled with d-band electrons compared with less-filled d-band electrons such as Zinc, Aluminum, & Magnesium.
Installing Sacrificial Anodes is exponentially beneficial to your business financially:
Structures by prolonging its lifespan and protecting it from deteriorating materials that is caused by the environment.
It is easy to install and maintained by trained personnel.
It doesn’t require any external electrical current.
It is less expensive to install than the counter part of Cathodic Protection Systems.
In this illustration, it portrays the system of how Sacrificial Anode Cathodic Protection Works. The Anode discharges electrons through the electrolyte, traveling to the Cathode, controlling its corrosion potential; thereafter, the Anode releases ions through the electrolyte, losing its metals. The cycle continues until the Sacrificial Anode reaches its limit for replacement.
Connecting Sacrificial Anodes to Cathode Structures?
When the Metal (Cathode) to be protected is inspected and carefully planned on where to install. Sacrificial Anodes are fabricated and delivered with Wired or Strap connections to the Cathode Structure.
Some anodes come with wires attached usually made of lead, these wires can be welded or bolted mechanically onto the structure. These wires are insulated to prevent damage and ensure they work without fail.
On the other hand, some may come in with Stap Connections where metal straps are built into the Sacrificial Anode, where these straps are usually welded directly to the Cathode.
Either Connections is concerned. These types of connections should contain low resistivity and should be insulated. Where good flow of electrons from the Sacrificial Anode to the Cathode must be secured for its purpose to be fulfilled.
Cathodic protection is used globally to fight against harsh environments such as soils, bodies of water and contaminated concretes. Some of the common applications are:
Storage tanks in harsh environments:
Underground and underwater tanks
Bottom areas of above-ground tanks on corrosive ground
Insides of crude oil tanks with salty water layers
Tanks holding seawater or untreated water
Offshore structures:
Oil rigs and platforms
Underwater oil extraction equipment
Wind turbine foundations in the sea
Tidal power generators
Oil and gas well components:
Protective tubes lining the wells
Water control structures:
Flood barriers
Canal and dock gates.
Construction materials:
Metal supports inside concrete structures
Although we’ve listed all the common applications of Cathodic Protection, we’re curious on what type of metals are we going to use beside one of the rules that you must choose a type of metal that has higher reducing potential than the metal to be protected.
Now that we’ve known what’s the best metals to be used as Sacrificial Anodes in terms of their Electron Configuration and Higher Reducing Potential. We must use what is best and fits on different bodies of water or soil:
Zinc is great for protecting metals in salty seawater. It's been the top choice for making protective anodes for years. However, zinc doesn't work well in less salty or fresh water. In these environments, we need to use different metals for protection.
Aluminum is now the top choice for protective anodes. It works well in both salty and somewhat salty water. Compared to zinc, aluminum anodes last longer and are lighter. This makes them more efficient and easier to use in many water environments.
Magnesium is best for land pipelines and freshwater use. It's more powerful than zinc or aluminum in less conductive environments like soil or fresh water. This makes it the top choice for protecting metals in these conditions.
Curious about sacrificial anodes? They are an excellent corrosion protection option every expert should consider.
If corrosion threatens your materials, investing in cathodic protection is essential.
At ESC, we offer zinc and aluminum sacrificial anodes, giving you a choice of top materials
for your corrosion protection systems. Get the supplies you need to safeguard your equipment today! Email us at anodes@esccorrosion.com or reach out to one of our offices near you!