Corrosion Protection Measures on an All-Aluminum Body

A body shell manufactured entirely of aluminum alloys is generally regarded as being insensitive to corrosion. The following paper confirms this assessment but specific types of corrosion affecting aluminum have to be avoided. The experience on which it is based includes vehicles with aluminum components driven in the field by customers, but is mainly derived from corrosion testing on specimen components and complete vehicles performed during the course of development. The most critical type of damage occurring is contact corrosion caused by other metals and conductive plastics. If the conversion coating on the metal is unsuitable, paint adhesion is insufficient and the characteristic aluminum filiform corrosion will start to form. Corrosion in crevices and beneath accumulated dirt is also likely to occur. This paper describes suitable protective measures, and also refers to repair techniques designed to avoid corrosion.