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The compatibility of magnesium die casting alloys with commercial automatic transmission fluids was studied in laboratory tests. The effects of high temperature, presence of water, and galvanic coupling with steel were examined, using visual observation, weight change, Scanning Electron Microscope, and Scanning Auger Microprobe surface analysis. No significant corrosion of magnesium was detected under any of the test conditions.

Selected metallic platings and insulating coatings on steel fasteners were evaluated for ability to reduce galvanic corrosion of die cast magnesium in a modified salt spray test. Proprietary electroplate systems based on zinc, zinc-nickel, zinc-cobalt and tin-zinc were tested, along with a commercial 50-50 tin lead alloy electroplate without supplementary coating. A proprietary liquid-applied zinc-rich inorganic coating successfully used on automotive fasteners was also tested for compatibility with magnesium. Encapsulation of bolt heads with plastic insulating coatings or special molded caps was evaluated. Interruption of the continuous salt spray by rinse and bake cycles was investigated as a likely exposure condition for magnesium assemblies in powertrain or underhood applications. Several of the protection schemes were found to effectively eliminate galvanic corrosion of the magnesium.

This paper describes the methodology by which a combination die cast magnesium and extruded aluminum door frame was developed using a current production steel door design as the base model for comparison. Product performance data, such as side impact requirements and overall door stiffness, along with the packaging of existing internal hardware, is presented. The results are verified by computer modeling. A prototype casting was produced to validate and compare castability requirements and geometry constraints of the door frame. An economic study is included that investigates the potential of developing such a system suitable for production. The results suggest that economic benefits may be obtained by using such a lightweight door system compared to an existing steel door design.