Investigation of the formation of physical damage on automotive finishes due to acidic reagent exposure

Abstract

SYNOPSISAutomotive paints with clear-coat surfaces can be physically damaged by exposure to acidic reagents produced in a smog chamber designed to reproduce real environmental conditions. Visual and reflectance microscopy observations show that deposition of material formed from the reaction of the clear coat and the reagent drop occurs on the paint surface after the drop evaporates to a critical size, with the greatest deposition occurring at the edge of the drop. This type of deposition suggests a free-energy minimization process favoring the formation of stable nuclei at the reagent drop edge. With heating after the drop evaporation to simulate exposure to the sun, a damaged area containing sulfur that is in the shape of a circular ring is observed at the location of the deposits. The majority of the visual damage appears to result from a n interaction between the deposit and the paint a t elevated temperatures. Results from profilometry, scanning electron microscopy, and reflectance microscopy show that the damaged areas are ring-shaped cracked blisters on the surface resulting from the clear coat separating into layers. 0 1993 John Wiley & Sons, Inc.

Automotive clearcoat damage due to oviposition of dragonflies

“…The degree of chemical attack decreases in the order HNO 3 > CH 3 SO 3 H, Cl 3 CCO 2 H > H 2 SO 4 > HCl > formic acid > acetic acid ∼ propionic acid (Table II). The damage increases with time if the attacked area is not immediately washed with water, which is in agreement with the literature 6.…”