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.