Hard Coat Anodizing
Hardcoat anodizing known as Type III, as named by MIL-A-8625. It is similar to standard anodizing, as it also creates a film of aluminum oxide on the part. This oxide layer acts as an insulator and can be dyed in a wide variety of colors. Hardcoat anodizing however, produces a much thicker coating of aluminum oxide greater than 25 microns. The key difference is that hard coat aluminum anodizing provides a surface that is more wear resistant and has a smoother and harder finish than standard anodizing. Hard anodizing is commonly performed clear, brownish or with a black dyed finish but colored hard coat anodizing can also be done for aesthetic purposes.