Anodizing is a process that is a combination of science and nature to give extruded aluminium profiles a good surface finish. The following image shows an extruded profile which is anodized for further improvement in surface finish.


Anodizing is basically an electro-chemical process. Anodizing employs electrolytic oxidation of the aluminum surface for thickening and toughening the naturally occurring protective oxide film. Surface finish especially in cases of architectural purposes improves a profile's durability and the most popular technique for such is anodizing. Amongst other things an anodised profile does the following things:

• Creates a surface that is dirt repellent and satisfying stringent hygiene requirements.
• Creates a surface that is “touch-friendly”.
• Provides the surfaces with an electrically insulating coating.
• Preserves the "new” appearance of a profile.

A very simple process of anodizing is shown in the following diagram:


Characteristics of Anodized Aluminium
The following table takes a good look at types of anodizing and their features and applications. However it must be remembered that it is only a guide, and any particular application should be done in consultation with an expert.

Properties	Natural anodizing	Colour anodizing
		Spray-/dip colouring	Electrolytic colouring
Indoors	Recommended	Recommended	Recommd.
Outdoors	Recommended	Recommended for few colours	Recommd.
Ultraviolet resistance	Very good	Good	Very good
Corrosion resistance	Very good	Very good	Very good
Chemical resistance	Good	Good	Good
Resistance to wear	Very good	Very good	Very good
Adhesion	Can be integrated with the base metal	Can be integrated with the base metal	Can be integrated with the base metal
Colour consistency	Very good	Good	Good

The main benefits of anodizing process is discussed in the next section.

Advantages of Anodizing

• Durability
  Anodized profiles have a life span that is extremely long along with offering significant economic benefits on account of less maintenance and operational savings. Anodizing is a sort of reacted finish which is integrated with the aluminum lying beneath for a perfect bonding and an unmatched adhesion.
  
  
• Color Stability
  Anodic coatings done on the exterior gives excellent stability from ultraviolet rays, The colours do not peel or chip.
  
  
• Simple maintenance
  Anodizing protects from scars and wear resulting due to fabrication. There is virtually no requirement for cleaning the surface dirt frequently. Only rinsing or cleaning with mild soap and water cleaning is enough to restore the original form of anodized surface.
  
  
• Aesthetically pleasing
  Anodizing offers a large range of gloss and color options along with or eliminating or at least minimizing color variations. Anodizing permits the extruded aluminum profiles to retain its metallic appearance.
  
  
• Cost
  A combination of lower initial finishing cost and lower maintenance costs work in the favour of anodizing.
  
  
• Health and Safety
  Anodizing is a very safe process and not injurious to human health. It is chemically stable, is non-toxic, and will not decompose.