Type III Anodizing , also known as Hardcoat Anodizing or Hard Anodizing, is similar to Type II Anodizing, but creates a thicker, more durable layer of aluminum oxide on the surface of the finished part. This is accomplished by manipulating the current density and bath parameters. After this process, the resulting finish has superior wear and corrosion resistance. As with Type II Anodizing, the finish is integral to the part as it penetrates the part as well as builds up on the surface.
The anodizing process is one of the more environmentally-friendly metal finishing processes. Since the anodizing process is a reinforcement of a naturally occurring oxide process, it is non-hazardous and produces no harmful or dangerous by-products.
Benefits of Hardcoat Anodizing include:
High corrosion resistance
Build up of worn surfaces on aluminum
Improved color and appearance. Hardcoat anodize coatings may be dyed, as with Type II. The resulting colors are not as vibrant.
Extreme wear resistance
Hard durable surface
Hardcoat (Type III) anodizing works very well with 6000, 5000, and 7000 series alloys of aluminum. High-copper alloys should be avoided when possible.
Typical Industries and Applications
Type III Anodizing is used in the following industries:
Machinery, for its wear resistance especially with high-speed machine parts
Electronics, provides constant emissivity
Marine, for its corrosion resistance, especially with salt-water
Oil, for its excellent corrosion and wear resistance
Air and Space, for durability, longevity, and light weight
Cookware, for corrosion protection and non-stick properties