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A STUDY OF THE EFFECTS OF ACIDIC POLLUTANTS ON AUTOMOTIVE FINISHES
Citation:
Rungsimuntakul, N., D. White, R. Fornes, R. Gilbert, C. Zhang, AND J. Spence. A STUDY OF THE EFFECTS OF ACIDIC POLLUTANTS ON AUTOMOTIVE FINISHES. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/A-92/237.
Description:
Automotive finishes of various compositions on metal substrates were exposed vertically in a smog chamber to UV and acidic atmospheres. he pollutants were generated from combinations of SO2, NO, propylene, water, and air. ews of different compositions were generated and collected twice a day. pot tests were performed by placing drops of (100 uL) of dews on the surfaces of the paints and heating in an air-circulating oven at 90 degrees C for 24 hours. isual observation, reflection optical microscopy, profilometry, SEM, and EDS were used to examine surface damage. arious degrees of damage occured depending upon the dew composition and surface properties. n general, the damage areas were in the form of rings with diameters smaller than the original drop. fter rinsing and buffing, the damage was still visible. icroscopy and SEM revealed that the rings consisted of numerous small areas of damage and that swelling, pitting, blistering, and cracking had occurred. DS showed aluminum and sulfur at the damage surface, whil the surrounding areas did not. ince the base coat contained A1 flakes, this suggested that the acidic dew nad penetrated through the top coat into the base coat.