An extensive atmospheric corrosion test program to simulate automotive field conditions has been undertaken. The aim of this project is to identify the necessary and sufficient key corrosion variables in appropriate dosage levels in order to design an indoor general purpose accelerated corrosion test.
This approach is based on a careful study of outdoor conditions that an automobile typically would encounter along with inputs from current understanding in the area of corrosion and material properties. A 26-3 factorial design was used to implement this test program. Simulating conditions such as humidity, temperature cycling, acid and/or salt depositions, generation of dew and the presence of minute amounts of air pollutants have been achieved by the design and implementation of a high performance climate chamber.
A large matrix of painted metal substrates and some bare metal samples along with previously studied AISI samples constitute this study. Outdoor exposure included panels mounted on vehicles, exposure at various global field sites as well as different variations of outdoor scab-testing.
Chemical, physical and morphological characterization of selected samples will be made using surface analytical techniques such as XPS, Auger, SEM/EDAX and TOF SIMS. Another facet of this study involves on-line monitoring by electrochemical impedance spectroscopy of the corrosion in progress in the indoor study.