Comparative corrosion analysis of acrylic precoated aluminum foil under natural exposure and neutral salt-spray (NSS) testing

Conducting research on the corrosion behavior of condenser fins is of great significance for evaluating the performance of the air conditioner during service. The corrosion behavior of precoated aluminum foil for air conditioner condenser fins after natural exposure test and neuter salt-spray (NSS) test were investigated through surface morphology, chemical composition, contact angle and electrochemical analysis. The results showed that there were significant differences between the microenvironment surrounding air conditioner condenser fins and the natural atmospheric environment. The operating status, the air conditioner model, and the ambient atmospheric conditions will influence the microenvironment of the fins. The precoated aluminum foils exhibit the identical same corrosion characteristics in both natural exposure test and NSS test with corrosion mainly observed in the edge region. Compared with the sample after NSS test for 60 days, the sample after natural exposure test for 2 year had lager corrosion extension distance of edge area, smaller low-frequency impedance modulus and larger contact angle, which indicated more severe corrosion. The comparative analysis of results indicates that the NSS test recommended by standards for a duration of 500h-1500h cannot accurately evaluate the service performance of precoated aluminum foil used in air conditioner in marine atmospheric environment.