Check whether two metals are suitable for direct contact and estimate galvanic corrosion risk under the selected service conditions.
| Pair | Typical Dry-Service Risk | Wet / Marine Risk | Common Protection |
|---|---|---|---|
| Aluminum + Stainless Steel | Low | Moderate to High | Isolation, coatings, sealants |
| Aluminum + Copper | Low | High | Electrical isolation and protective coatings |
| Carbon Steel + Copper | Low | Moderate to High | Isolation and moisture control |
| Zinc + Copper | Low | High | Isolation / compatible plating |
| Carbon Steel + Stainless Steel | Low | Moderate | Isolation in conductive environments |
| Titanium + Aluminum | Low | Moderate to High | Isolation and coatings |
| Titanium + Stainless Steel | Low | Moderate | Isolation where required |
| Copper + Brass | Low | Low to Moderate | Environment control where necessary |
What is galvanic corrosion? Galvanic corrosion occurs when dissimilar metals are electrically connected while exposed to an electrolyte. The more anodic metal can corrode preferentially.
Can two different metals safely touch when dry? Often yes, because a dry environment lacks the electrolyte needed for a sustained galvanic cell. However, condensation or contamination can create localized wet conditions.
Is aluminum touching stainless steel safe? It can be acceptable in dry environments, but galvanic corrosion can become a concern in wet, salty or marine environments. Electrical isolation is commonly used.
Can copper and aluminum be connected together? They can be joined in engineered systems, but direct contact in wet environments can create galvanic corrosion and electrical-connection problems. Appropriate connectors, compounds and isolation methods are important.
Is stainless steel always corrosion-proof when touching another metal? No. Stainless steel can act as a relatively noble cathode in a galvanic couple, potentially accelerating corrosion of a less noble metal under suitable conditions.
Why does area ratio matter? A small anodic area connected to a much larger cathodic area can produce a high local corrosion current density on the anodic metal, making the arrangement particularly unfavorable.
Does a coating eliminate galvanic corrosion? A complete electrically insulating coating can interrupt the galvanic circuit. Partial or damaged coatings can sometimes create unfavorable localized conditions, so coating design matters.
Does seawater increase galvanic corrosion risk? Yes. Seawater is a relatively conductive electrolyte and can support galvanic currents between electrically connected dissimilar metals.
Can this calculator predict corrosion rate? No. It is a compatibility screening tool. Quantitative corrosion prediction requires material-specific electrochemical data and detailed service conditions.