How GMN Automotive prevents galvanic corrosion

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By Richard Smylie | Nov 30, 2015
Automotive fuel label

Producing automotive parts requires meeting exceedingly difficult quality and durability standards, especially for exterior vehicle components. These parts not only have to meet mandated safety, design, and industry performance standards, but also must withstand exposure to some of the world's most challenging environments. Despite these challenges, GMN Automotive has the process capabilities and knowledge required to meet and exceed tough external environments.

One of the major challenges facing metal components utilized in automotive exterior applications is galvanic corrosion. Galvanic corrosion results when two different metals come in electrical contact with one another in the presence of an electrolyte (for example a salt water solution) because it causes an electromechanical process in which one metal corrodes preferentially to another. Over time this causes the metal to deteriorate, compromising the component’s visual and functional intent. The metals that are typically affected by galvanic corrosion include aluminum, zinc, and magnesium.

This reaction presents many challenges when producing various metal exterior automotive components, especially wheel badges. Many exterior wheel badges are constructed to include a decorative aluminum or stainless steel center cap that is adhered into a chrome plated overlay. Due to exposure to the elements and the nature of the two differing metals, the more active metal, which would be the center cap, tends to corrode. Galvanic corrosion is one of the main failure modes for wheel badges and center caps, especially in colder climates where roads are dusted with salt (an electrolyte) to prevent ice in the winter months.

Our solution to overcome this challenge? GMN Automotive has developed proprietary corrosion resistant coatings and pre-treatments that are utilized with two other GMN Automotive capabilities, insert and over molding. These capabilities create a construction that encapsulates the raw edge of the center cap and thus eliminates the possibility of the two differing metals from coming in contact with one another. This means that galvanic corrosion is prevented from occurring and parts can better withstand external environments.