WHAT IS ANODIZING?

Anodizing successfully combines science with nature to create one of the world's best metal finishes. Developed over 50 years ago, anodizing is an electrochemical process that forms a protective coating of aluminum oxide on the surface of the aluminum.

Raw aluminum left exposed will corrode and oxidize, creating weakness and becoming unsightly. Anodizing protects the raw aluminum, transforming it into a hard and durable, weather-resistant substance.

Anodized coatings can be colored by dyeing - and because anodizing is a chemical bond to the metal, these colored coatings cannot flake or peel. The microscopic structure of an anodized coating consists of many small hexagonal pores. These are filled with a sealer that hydrolyzes the pores to create a smooth, durable surface.

Basic steps in the anodizing process

Successful execution of the anodizing process is key to producing a high quality, long-lasting coating for your product. However, there is much more to the process than meets the eye.

1. Cleaning

To assure a consistent finish, it is very important to start with a clean product - which is why Pilkington has invested in a comprehensive pretreatment program.

Because cleaning is so critical, you should always confirm that this step will be included as part of the anodizing process. At Pilkington, your product is cleaned using one or more of the following methods:

2. Mechanical and Chemical Pre-Treatments
After cleaning, your product is pre-treated to achieve the desired degree of reflectivity. Again, the quality of your finish depends upon skilled execution of these pre-treatment techniques, which can be used to create three different finished looks:

3. Treatment

This is the step where your product is actually anodized. However, you should be aware that not all anodizing treatments are 'created equal'. To assure the very best in quality, Pilkington uses MIL-A8625 Type II and Type III certified treatments. Your anodizing options include:


4. Finish

During the last step of the anodizing process, the final finish is achieved through application of:

Hardcoating - for maximum durability

Hardcoating, which is an extension of the standard anodizing process, results in a protective finish that is up to 8 times thicker and 10 times more durable and wear-resistant than standard anodizing. One of the unusual features of hardcoating is its extremely dense and hard structure, which results in a high degree of lubricity - i.e., hard-coated surfaces can run against each other without lubrication in some applications.

Other properties of hardcoating include: super long life span, resistance to outdoor conditions, exceptionally hard surface, easily cleaned and heat resistant. Hard coating has applications in industries where components require wear-resistant surfaces - for example, cylinders, hydraulic gears, and machine ways.

There are several variations of hardcoat anodizing. Thus, when 'hardcoat' is specified, it is useful to know the product requirements or the situation for which the product will be used.

Bright dipping - the ultimate look in anodizing

Bright dip is an especially brilliant finish achieved by using the bright dipping process. Because bright dip's attractive gloss finish helps accent colors as well as graphics and lettering, it is sometimes referred to as the 'ultimate look in anodizing'.

Pilkington offers bright dip anodizing in a variety of colors - an option not available at most metal finishing firms.

The advantages of anodizing

As a Pilkington customer, you can take advantage of the many benefits offered by high performance anodized finishes.

Durability

Anodizing results in a complete bonding of the finish coating and the aluminum - so the finish cannot peel off because it is actually part of the metal. An anodized finish is chemically stable and heat resistant to the melting point of aluminum, which occurs around 1,221 degrees F.

Cost

Due to their extremely long life span, most anodized products offer significant economic advantages. Lower maintenance costs combine with lower initial finishing costs for substantial savings and greater long-term value. In addition, because the anodizing process is very efficient, products can be delivered quickly to meet today's demanding production schedules.

Color Stability and Selection

Anodizing gives aluminum a deep, rich metallic sheen. The anodized coating is translucent, which is why the aluminum retains its metallic appearance after it is anodized. One of the key advantages of anodizing is color stability. Exterior anodized color coatings do not chip or peel and are resistant - though not impervious - to ultraviolet rays.

For standard anodizing, Pilkington offers a palette of twelve popular colors, as well as custom colors where quantity warrants.