Chemical depth profiling of multi-layer automotive coating systems

Abstract Detailed chemical analysis of high performance automotive coating systems can be done with a relatively available and affordable set of measurement technologies, including infrared (IR), ultraviolet–visible (UV–Vis) and optical microscopy (OM) based methods. These tools are very versatile in the ability to do both surface and interface characterization, as well as depth profiling. Their utility is illustrated using a broad range of applications: surface-specific defect analysis; stratification/segregation of network components; mechanisms/kinetics leading to coating degradation and material loss; UVA permanence in coating systems; and UVA interphase mixing between clearcoats and BCs. Many of the studies were conducted as a function of exposure time and conditions (i.e., outdoor/field environments; accelerated aging via QUV, UV only, CHC or xenon borosilicate/borosilicate protocols) or application conditions. Albeit the focus of this work is on chemistry and associated changes while in use, correlations to appearance, physical properties, and mechanical performance will be noted to underscore significance of the changes in chemical composition. Also, sampling techniques used in isolating chemical species or isolating bulk material from a given depth locus will be shown for each application. Since the approaches described herein do not require expertise/equipment that is available to only a few, these works should highlight the potential utility of such tools.