New Quality Control Test for Anodized Aluminum

This paper reviews briefly many of the tests currently being used to evaluate the quality of anodized aluminum, particularly that used for automotive trim applications. The advantages and disadvantages of each are related to the need for a more quantitative rapid test. A new quality control test developed by Alcoa for use with anodized aluminum is presented for consideration by the automotive industry. This test, based on the measurement of impedance of the anodized coating, is rapid, nondestructive, adaptable to different configurations, economical, independent of alloy, and highly discriminating with regard to coating thickness and seal.