Surface Treatment Techniques for Aluminum Extrusions

Aluminum extrusions naturally have a surface with corrosion resistance. This is the character of aluminum. No need to do extra surface treatment if no any strict requests on super corrosion resistance or decoration. But if you have these requests, there will be various surface treatments on the extruded aluminum surface, and each has its purpose and application. 

In FONNOV ALUMINIUM, the aluminum surface treatments include anodizing, powder coating, liquid painting and wood-finish sublimation. There’re also mechanical surface treatments include sandblasting and polishing. Now let’s see what it is for each treatment technology. 

Anodizing

Anodizing is the oldest surface treatment method for aluminum and aluminum extrusion. Anodizing aims to protect aluminum for a higher corrosion resistance and make its usage for a longer time. When anodizing, there will form an oxide layer on the aluminum surface, this is a clear protective film, and thickness are generally 5-25um. The oxide layer also can be colorful, including black, red, yellow, brown, purple, green, pink, etc. This great decorative value makes anodizing a wide use on many final products. 

Powder Coating

Powder coating is an eco-friendly surface treatment technology. No harm materials are used when applying the powder coating. It is also called a more environmentally friendly alternative to painting. The powder coating is applied by an electrostatic process. The negatively charged powder is hereby applied to the aluminum object which is positively charged, this creates a temporary adhesion on coating and aluminum surface. After curing, the coating melts and flows, and this temporary adhesion becomes a firm adhesion. The thickness of this film is generally 60-120um, which is also the thickest among these surface treatments, so this finish offers an extra layer of protection from corrosion, scratching and chipping. The primary purpose of powder coating is to provide a decorative finish on aluminum products. Applicators tell the coating factory a RAL number or Pantone number, and they can get the color result by powder coating. Some particular fields need durable or corrosion-resistant coatings, so special powder coating also provides a super protective finish. Its surface appearance is different from anodizing and liquid painting. Powder-coated aluminum is widely used in architecture and building construction. 

Liquid Painting

Liquid painting is ideal for products that demand a thin, smooth and bright finish. The liquid painting is sprayed evenly onto the aluminum surface. PVDF finish is produced by liquid painting. This finish provides an excellent protection against the harsh environment. 

Woodgrain Sublimation

FONNOV ALUMINIUM use a sublimation process to create a wood finish on aluminum extrusion. Before the sublimation process, the aluminum profiles must be powder coated and cured. A printed paper/film will be covered on the painted surface and vacuum them to be close and then cured. A clear woodgrain finish will get on aluminum surface after tearing the paper off. This technology makes aluminum material surface closer to nature. This woodgrain finish is mainly used on interior and exterior architectural design. 

Mechanical Treatment

FONNOV ALUMINIUM applies sandblasting treatment and polishing treatment as an auxiliary method for the anodizing finish. These mechanical methods always are done before anodizing. Polishing and anodizing create a brighter anodizing surface, and sandblasting anodizing makes extrusion lines unclear. 

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