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Enhancing the Durability and Aesthetic Appeal of Aluminum

Aluminum anodizing is a unique electrochemical conversion process developed for protecting aluminum alloy surfaces from corrosion and wear. This treatment forms a thin oxide film on the surface of an aluminum component, resulting in a hard, durable, and aesthetically pleasing coating.

There are many different types of aluminum anodizing, but the most common are Types I, II, and III–Chromic acid, sulfuric acid, and hardcoat anodizing, though chromic acid is no longer as prevalent as it was when anodizing was first developed.

Type I: Chromic Acid Anodizing

Type I aluminum anodizing results in the thinnest possible coating of the three main types, and when properly sealed, offers excellent protection against corrosion as well as a non conductive surface. While this type is good for welded parts and assemblies, it tends to be more expensive and has several health and safety concerns due to the use of chromium.

Type II: Sulfuric Acid Anodizing

Type II is the most common aluminum anodizing method, being much more cost-effective than the other types and also much more flexible. Sulfuric acid anodizing is best suited to applications that require both a high level of hardness and abrasion resistance as well as corrosion protection.

Type II anodizing involves placing an item into a sulfuric bath in order to form the oxide layer on the surface. This treatment is often preferred due to being not just corrosion resistant, but also highly durable and dyeable as well. Its more porous surface absorbs a wide range of dyes, offering many different finishes and colors for the part. Type II also has other benefits, resulting in a nonconductive and gall-preventative surface. It’s also highly flexible, able to treat many different alloys, making it excellent for a wide range of aerospace, medical, electronic, and defense applications.

Sulfuric acid anodizing is typically used to treat parts such as hydraulic valves, pistons, aluminum parts for military weapons, tire rims, mechanical hardware, computer and electronic enclosures, lighting fixtures, robotics and more.

Type III: Hardcoat anodizing

Type III anodizing is much thicker than conventional aluminum anodizing (Type II) and is typically used when components require increased surface hardness, thermal and dialectical properties, and high abrasion and corrosion resistance.

Hardcoat anodizing is one of the most flexible and versatile types of aluminum anodizing, and can be employed in a nearly endless number of combinations of aluminum substrates, colors, and seals. The basic process of it is fairly simple–the part is connected to an anode and submerged in an acidic solution, where a current is drawn across the part, depositing aluminum oxide onto the surface.

Typically, Type III aluminum anodizing is used in applications where the components will be subjected to extreme conditions of abrasion, corrosion, and everyday wear. This type of treatment results in a thicker, harder, and far more durable coating than other anodizing methods, and it’s also valued for its electrical insulation. Hardcoat anodizing also offers many other benefits, being able to repair worn aluminum surfaces and improve the part surface for slide applications.

Hardcoat aluminum anodizing is excellent for aerospace, automotive, food manufacturing, robotics, and industrial applications. It’s most often used to treat valve components, pistons, sliding parts, hinges, cams, gears, insulation plates, swivel joints, and more.

Looking for a supplier of anodizing services?

Gleco Plating offers a wide range of finishing solutions for our customers, including Type II and Type III aluminum anodizing. Check out our website to learn more about all of the services that we offer.