The effect of time and heat exposure on the wettability and glossiness of CAA and FPL coatings for aluminum substrates

Abstract

The use of anodized coatings as a substrate for adhesive bonding of aluminum is widespread and generally accepted. However, with time and exposure to heat, the coating’s behavior changes and its wettability decrease. We examine the coating’s wettability by measuring the contact angle. Aluminum sheets are coated with two types of anodizing and FPL coatings for this study. The results indicate that the wettability of all coatings remains stable for 16 h post application. However, there is a significant decrease in wettability over extended time periods, with the anodized coating exhibiting more pronounced changes after 30 days compared to the FPL coating. Also, in both types of coatings, as the heating temperature increases, the wettability decreases and the contact angle increases. The changes in the anodized coatings are more pronounced than in FPL coatings. Measuring the glossiness of the coating before and after heating shows that the gloss and the surface roughness of the coating remain unchanged.