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Driven by legislation in the European Union (ELV directive 2000/53/EC [1]) and international industry activities for the use of environment-friendly technologies, automotive suppliers and OEMs are faced with the demand to substitute lead-containing solders in electronic assemblies. Compared to consumer electronics, for which lead-containing technologies had to be phased out by July 2006, automotive applications have to meet considerably higher requirements concerning lifetime and environmental loading conditions, which mainly result from superimposed vibrations and temperature cycling. Therefore, advanced reliability testing and damage analysis techniques are needed to ensure a reliable use of lead-free solders. This paper presents the results of reliability tests that aimed at assessing the capabilities of different analysis tools to characterize solder joints for quality assurance and damage analysis.

The hatchback of Volkswagen's 3 liter car (3 l fuel consumption per 100 km) consists of an inner component of die casting magnesium (AM50) covered with an aluminum panel from the outside. This hybrid design requires a new manufacturing process: The pre-coated magnesium part will be bonded and folded with the bare aluminum part. Corrosion protection is provided by an organic coating system which both protects against general corrosion and galvanic corrosion. The corrosion of the Al / Mg sandwich has been examined with hybrid samples which are similar to the hatchback. Several powder coatings (epoxy resin, polyester resin, hybrid resin), wet paints and cathodic electro-coating paints of different thicknesses and compositions have been applied to the magnesium part. They show that only powder coating provides adequate protection. Galvanic corrosion at the points of attachment of the hatchback might be possible (for example the bolted joint of the hinge).