Effect of Mill Run and Temper Variations on Barrier Anodic Film Formation on 6061 Aluminum Alloy

摘要

We have evaluated the relationship between barrier anodic film formation and variations in the composition and microstructure of 6061-T6 aluminum alloy samples from three different mill runs. We also studied the characteristics of coatings formed on 6061 alloy samples with more extreme microstructure differences produced by two of heat treatment. The differences between the coatings formed on samples from the three different mill runs are small. Large differences occur in the processing characteristics and dielectric properties of coatings formed on heat-treated 6061 samples compared to the 6061-T6, as-received stock. Samples which have been heated to 500 exp 0 C and cooled slowly take substantially longer to process compared to 6061-T6 as-received stock, and 500 exp 0 C, rapid-quenched samples. The coatings on 500 exp 0 C, slow cooled samples display substantially inferior dielectric properties. The anodization characterisitcs of annealed vs work-hardened, pure aluminum samples which we studied the different coating characteristics displayed by the treated alloy samples are related to differences in the size and/or distribution of precipitates associated with the alloying components. (ERA citation 10:000913)