Aluminium has an excellent appearance and is corrosion resistant by nature. However, in order to improve the corrosion protection and other properties of aluminum, we use various types of surface treatment. With certain methods, the following properties can be influenced:

• Color
• Hardness
• Friction
• Electrical insulation
• Surface texture

Our principally used surface treatment methods to optimize the aluminium product are anodizing, powder coating and wet painting. All three types seal and protect the extruded aluminium profile and give a wide selection of color options with varied sheen and excellent consistency. Surface treatment also often includes pre- and post-methods such as etching, polishing, blasting, grinding, wrapping and printing.

When surface treatment is required, Hydro has a range of solutions which ultimately strengthen the advantages of aluminium and provide an attractive finish. With a more durable, long lasting product the need for replacement is reduced which has positive environmental implications.

Anodizing

Our most frequently applied surface treatment method with a comprehensive list of benefits is anodizing. Our in-house anodizing lines allow for a ‘one stop shop’ with short lead times when purchasing your aluminium profiles and components with a quality assured finish. In our extrusion plants in the DACH region, we offer you a wide range of volumes, lengths and different color applications. Our experts will advise you to find the optimal solution for your individual application.

Anodizing is a process in which the outer surface of an aluminium profile is converted into aluminium oxide, a ceramic with unique properties, which is used to create a permanent new appearance. With anodizing, the oxide layer on the surface of the aluminium is made during an electrochemical process, the natural aluminium color can be maintained, but a variety of other colors are also available.

Anodizing is one of the oldest and more sustainable surface treatments of aluminium. Some of the main advantages of using anodizing are as follows:

• Easy to recycle (cradle to cradle)
• Easy to reuse (circular economy)
• Aesthetically pleasing, providing a decorative surface with durable colour and gloss
• Corrosion resistant
• Improved wear resistance
• Gives a smooth finish
• Offers surface hardness
• Creates additional durability and is able to recondition
• Has a reflection ability
• Provides electrical insulation
• Significantly reduces the risk of filiform corrosion, chipping, flaking, peeling or chalking
• Provides a specific surface structure
• Anodizing is used as a pre-treatment for powder coating as well, the pre-anodization layer guarantees an extra durable conversion layer for the final coating layer.

Powder Coating

During the powder coating process, a free-flowing dry powder is electrostatically applied to add colour or finish effects. It is then cured via heat treatment or UV lights. The advantages of powder coating lie in the combination matrix of color, function, gloss and corrosion properties.

Some of the key highlights of powder coating include:

• Achieving a precise color match
• Offers an extra layer of protection from corrosion, scratching and chipping
• Can provide a thicker coating than alternative options
• Provides a long-lasting durable finish
• Powder coated surfaces are of high chemical and mechanical resistance
• Thickness can be chosen from very thin (approx. 20µm) to max. 200 µm
• Can cover some surface deviation of the base material

Wet painting

Wet painting can produce a wide range of liquid color paint and is ideal for products that demand a thin finish. Wet-blasting liquid paint is sprayed onto the surface to an even thickness of approximately 15-20 micrometers. Common applications of wet paint include for example automotive exterior with high glosses and interior with multiple functions, furniture and general industrial applications.

The main advantages of aluminium wet painting are:

• Gives a desirable finish
• Provides a smoother final finish
• Is heat resistant
• Offers corrosion resistance
• It is durable and offers a wide range of functional properties