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Technology / Engineering guide
Dissimilar Metals & Galvanic Corrosion in Wind Equipment
A corrosion review needs the joint’s material and exposure context. The names of two metals alone do not establish the behaviour of the installed interface, and a clean-looking surface is not proof of compatibility.
Follow both the electrical contact and the wet exposure.
Galvanic corrosion involves a conductive connection and an electrolyte as well as dissimilar materials. Describe the actual interface before interpreting a general material comparison.
01 / Mechanism
A galvanic couple needs more than two material names.
NASA Kennedy’s corrosion explanation identifies dissimilar metals, an electron-conducting path and an electrolyte as the galvanic mechanism’s context.
NASA Kennedy’s corrosion explanation identifies dissimilar metals, an electron-conducting path and an electrolyte as the galvanic mechanism’s context. These elements should be considered together rather than treating every dry juxtaposition as the same exposure.
The explanation is not a claim about a MARSTON material combination. List the actual joint, fastener and contacting parts when known; do not identify alloy or protection type from a photograph alone.
02 / Material identity
Alloy and surface condition belong in the comparison.
A generic word such as steel or aluminium is not a complete material designation.
A generic word such as steel or aluminium is not a complete material designation. The applicable alloy, surface finish and condition should be identified for the components being assessed. A nominally similar replacement may have a different surface system.
Keep the supplier’s material statement with its component revision. Material compatibility needs the assembled interface and environment, not an assumed interchangeability based on the appearance or size of the part.
03 / Conductive paths
Contact can extend beyond the obvious mating face.
The review should identify which parts provide electrical continuity across the interface and which paths remain relevant in the design.
The review should identify which parts provide electrical continuity across the interface and which paths remain relevant in the design. A washer or coating cannot be assumed to isolate a complete joint without examining the actual arrangement.
Corrosion control and required electrical bonding are separate design responsibilities that must be coordinated. Do not remove a conductive path or add insulation based on a general corrosion example; this page offers no treatment prescription.
04 / Wet environment
State where the electrolyte can be present.
Record whether the relevant interface can encounter rain, condensation, saline deposits or another stated conductive environment.
Record whether the relevant interface can encounter rain, condensation, saline deposits or another stated conductive environment. The important boundary is the surface condition at the joint, not only the nearest coast or a broad climate label.
Identify the basis of that description and combinations that remain unresolved. A laboratory exposure and the joint’s installed wetting history are different records; neither should be presented as the other without justification.
05 / Assessment scope
A finish claim needs its represented assembly.
Compare the assessed material combination, finish system, exposure and outcome with the offered interface.
Compare the assessed material combination, finish system, exposure and outcome with the offered interface. A coating result for an isolated specimen does not independently cover a bolted joint’s contacting surfaces and electrical requirements.
Likewise, an observed mark requires its own assessment; it cannot establish a universal corrosion rate or remaining life. Use the coastal guide for wider exposure planning rather than treating this mechanism as the whole environmental review.
06 / Supply changes
Keep interface substitutions visible.
If a supplier proposes different fasteners, contact parts or finishes, identify which interface assessment the change affects.
If a supplier proposes different fasteners, contact parts or finishes, identify which interface assessment the change affects. Retain the accepted combination and the responsible materials and electrical reviewers in the configuration record.
No specific alloy pair, corrosion category, protection grade or maintenance interval is asserted for MARSTON. The preload guide explains why the fastening conditions must also remain consistent when surface systems change.
Continue the review with Wind Turbine Flange Bolts: Preload, Torque & Conditions.
Continue the review with Wind Blade Coatings, Leading-Edge Erosion & Exposure.
Continue the review with Wind Converter Cooling, Thermal Ratings & Derating.
General background: NASA Kennedy: Galvanic-corrosion mechanism. These references explain industry concepts; they are separate from the applicable MARSTON product and project documents.
Prepare the information for this review.
Use the checklist to organise the project information. Mark unavailable items and retain document references.
| Review item | Information to provide | Purpose |
|---|---|---|
| Joint identity | Contacting parts, fasteners and revisions | Locate the material combination. |
| Material condition | Alloy designation and applicable surface system | Avoid conclusions from generic names. |
| Conductive path | Actual continuity and bonding responsibilities | Coordinate electrical and material functions. |
| Electrolyte context | Local wetting, deposits and evidence basis | Define exposure at the interface. |
| Change record | Proposed substitution and affected assessment | Preserve the accepted configuration. |
Engineering questions.
Are two different metals enough to describe the risk?
No. Conductive contact and the electrolyte environment also belong to the mechanism.
Does stainless appearance identify an alloy?
No. Use the applicable material and finish records.
Can I add an insulating washer from this guide?
No. Isolation, bonding and fastening require the actual joint’s approved design.
Does distance from the coast settle the question?
No. Local wetting and deposits at the interface matter.
Does a coating test prove every joint compatible?
Only its represented materials, exposure and configuration are covered.
Are MARSTON alloy pairs or corrosion rates specified here?
No. This guide explains review inputs without a product corrosion claim.
Technical enquiry
Bring your project information to the discussion.
A corrosion review needs the joint’s material and exposure context. Share the available information and the equipment scope you want reviewed in a technical quotation.