Galvanic corrosion is a prevalent but usually neglected problem when connectors of different metals are utilized. When two dissimilar metals are in contact with an electrolyte (e.g., water), an electrochemical reaction is initiated, and the less noble metal corrodes. In electrical systems, it can cause connections to become weaker, raise the resistance, and eventually result in equipment failure. This article discusses how galvanic corrosion can happen using various platings of connectors, the dangers it poses, and preventing it.
How Galvanic Corrosion Happens?
Galvanic corrosion occurs when there are three basic elements:
Two Dissimilar Metals – Metals are at different locations on the galvanic series (a graph that lists metals in order from most to least electrochemically active).
An Electrolyte – Water, moisture, or even condensation can be used as an electrolyte.
An Electrical Path – A physical contact between the two metals forms an electrical current, which initiates the corrosion process.
Two metals such as gold and silver or copper and aluminum when joined, the metal lower on the galvanic series (the more reactive one) will corrode as it donates electrons to the more noble metal.
Connector Plating and Galvanic Corrosion
Various connectors are plated with other metals for enhanced conductivity, durability, and oxidation resistance. Typical connector platings are:
Gold – Very corrosion and oxidation resistant; best suited for low-voltage and signal connections.
Silver – Good conductivity but more susceptible to tarnishing when exposed to sulfur or water.
Nickel – Offers durability and oxidation resistance but with greater resistance than gold or silver.
Chrome – For protective plating, but less conductive and can cause a potential difference between other metals.
Example Scenario:
When a gold-plated male connector is coupled with a silver or nickel-plated female connector, there will be a galvanic reaction. Gold is nobler than silver and nickel, so the silver or nickel part will corrode over time, particularly in the presence of moisture.
Risks of Galvanic Corrosion in Electrical Systems
⚠️ Raised Resistance – Corrosion on the connection point raises resistance, which causes heat buildup and can result in failure.
⚠️ Compromised Connections – Corroded connectors can loosen with time, resulting in intermittent signals or loss of power.
⚠️ Equipment Damage – When the corroded connector fails, it can damage attached equipment or initiate a short circuit.
⚠️ Signal Degradation – Corrosion can cause poor signal quality and loss of data in audio and data connections.
Preventing Galvanic Corrosion in Connectors
✔️ Use Matching Platings – Where possible, use bimetallic connectors plated with the same metal to reduce galvanic potential.
✔️ Use Dielectric Grease – A thin dielectric grease coating can form a barrier to moisture and help prevent corrosion.
✔️ Seal Connections – In outdoor or wet environments, seal connectors with heat shrink tubing or rubber seals to keep them dry.
✔️ Avoid Mixed Metals – If gold connectors are needed, do not mix them with silver or nickel parts unless the manufacturer specifically advises against it.
✔️ Use Corrosion-Resistant Coatings – Certain connectors are coated with anti-corrosion coatings that keep moisture out and oxidation at bay.
Galvanic corrosion between dissimilarly plated connectors is a potential hazard that can threaten the integrity and performance of electrical systems. Familiarity with the galvanic series and prevention of moisture and mixed-metal contact can both lower the risk of corrosion-related failure. Appropriate material pairing, protective coatings, and environmental controls are necessary to ensure long-lasting and dependable connections.