Most common process for commercial anodizing.
Films range from .0001"-.001" thick. The overall thickness of the coating formed mainly in penetration of the substrate (67%). Considering the preparation of the part, etch and deoxidized, there is no modification of the final dimensions of the part. This process adds minimal hardness and abrasion resistance. Sulfuric anodized film can be colored prior to sealing.
Many alloys can be processed. The film is thicker and harder than chromic anodize and even though the surface finish will turn light grey naturally, it can be colored. This type of anodizing is non-conductive and good for bonding.
Used in architectural extrusion and sheets, external structures (curtain wall), optical components, hydraulic valve bodies, as well as military applications, computer and electronic enclosures, mechanical hardware or paint/prime base.