Evaluation of automotive coatings is often completed using laboratory cyclic tests. These tests use onset of red rusting and scribe creep to give an estimation of field performance of the materials. The most common automotive laboratory cyclic tests take 2-4 months to complete.
These tests are oflen the rate limiting step in making progress toward product related decisions. This paper reports the use of EIS in combination with cyclic testing to estimate scribe creep performance. Materials were exposed in the GM 9540P-Cycle B laboratory test for 1 day or 8 days, and tested following removal from exposure. Material performance was compared to scribe creep performance after 40 days in the same test. Results of these studies will be discussed in this paper.