Tube-Fin Interaction - A Closer Look at the Corrosion Mechanism

Aluminium brazing sheet is widely used for the manufacturing of automotive heat exchangers. As far as corrosion resistance is concerned, the main issue is prevention of tube perforation, leading to premature field failures. Tube-fin corrosion interaction was studied using mini fin packs with different tube-fin combinations. The corrosion performance was tested using different accelerated tests and compared to individual coupon performance. It will be shown that the fin can have either a negative or a positive influence on the corrosion performance of the tube-fin system, depending on the selected alloy chemistry. Additionally, electrochemical characterisations were carried out on individual tubes and fins, which showed that these techniques could potentially be used as a quick tool to predict the corrosion behaviour of a tube-fin system.