Hard Anodizing, full name Hard Anodic Oxidation Treatment. The general requirement for the thickness of hard anodizing films is 25-150 micrometers, with most films ranging from 50-80 micrometers. Hard anodizing films with a thickness less than 25 micrometers are used for parts in applications such as gear keys and helical components, where wear resistance or insulation is required, and the anodizing film thickness for these purposes is approximately 50 micrometers.