February 17, 2026
How to Prevent Galvanic Corrosion
Galvanic corrosion, also known as bimetallic corrosion, occurs when two dissimilar metals come in electrical contact in the presence of an electrolyte, such as moisture, salt or a chemical.
Corrosion usually affects a single material, but galvanic corrosion often progresses much faster. This increases the risk of premature component failure, unplanned downtime and repair costs. If you work with mixed-metal assemblies, understanding material relationships is key to galvanic corrosion prevention.
Understanding Galvanic Corrosion
Galvanic corrosion is driven by differences in electrical potential between metals. When two metals with different potentials are connected, the more anodic metal sacrifices itself to protect the more cathodic metal. The greater the difference between the two metals, the faster the corrosion rate.
That’s why mixed-metal assemblies are especially vulnerable in harsh or outdoor environments. Exposure to humidity, washdowns or corrosive chemicals creates the electrolyte needed to accelerate the reaction. Over time, galvanic corrosion weakens structural integrity and compromises the fasteners on critical components.
Preventing Galvanic Corrosion Between Aluminum and Steel
A common misconception is that stainless steel offers superior corrosion resistance. However, while stainless steel performs well in many environments, it can actually accelerate corrosion or pitting in a more anodic metal when the two meet.
Aluminum is significantly more anodic than steel, meaning it corrodes rapidly when the two materials come in contact under the right conditions. If you use aluminum and steel together, the best solution is to isolate the metals with coatings and engineered surface treatments.
How Coatings Support Galvanic Corrosion Prevention
Properly selected coatings create a physical barrier between dissimilar metals and the surrounding environment. For example, coating stainless steel fasteners helps when they’re used in aluminum assemblies. By isolating the metals from direct electrical contact and limiting exposure to electrolytes, you can slow or even stop the galvanic reaction.
Another effective approach is to use carbon-steel fasteners protected with a zinc coating and an aluminum-rich top coat when fastening into aluminum panels or bodies. These engineered systems are designed to balance electrochemical potential while providing durable corrosion protection.
Why Application Knowledge Matters
Effective galvanic corrosion prevention depends on understanding how the assembly will be used, what it will be exposed to and how long it is expected to perform. Before choosing a coating, consider environmental conditions, mechanical stresses and compatibility with adjacent materials. When coatings are done correctly, they help maintain system reliability, reduce maintenance needs and extend equipment life span.
To learn how to prevent galvanic corrosion between specific metals like aluminum and steel, you can refer to the “Anodic Index” or “Galvanic Series” from Engineers Edge. These tools rank metals from most anodic to most cathodic, helping you predict the corrosion risk before it becomes a field issue.
Get Long-Term Corrosion Protection
Preventing galvanic corrosion requires a skilled and knowledgeable partner who understands your needs. At RIE Coatings, we specialize in advanced coating and finishing solutions designed to address complex corrosion challenges. With in-house processes, rapid response times and direct access to engineering expertise, we can help you protect mixed-metal assemblies with confidence.
If you need to prevent galvanic corrosion in demanding applications, get in touch with us today to speak to an engineer.