Anodizing is one of the oldest electrochemical processes. Changes the metal surface chemistry of the metal and other substrates. Coverts the surface into a corrosion resistant, decorative, resists scratching and is one of the most durable surface finished.

Anodize can be done in different non ferrous materials like magnesium, titanium and aluminum.

Benefits of Anodize Aluminum:

Corrosion Resistance

Anodized aluminum is more resistant to corrosion than standard aluminum. However, they can still corrode when exposed to moisture, air, salt or other corrosion-inhibiting compounds or elements. Anodized aluminum is less likely to corrode than standard aluminum because they have a thicker layer of oxide.


Unlike standard aluminum, anodize aluminum can be dyed to achieve any color or combination of color. Gallery of color anodize


While the best benefit of anodized aluminum is its superior resistance to resistance, it also features better lubrication than standard aluminum. Anodize Aluminum creates deeper pores in the metal that allow for greater retention of lubricating oil or film.

Increased adhesion

Anodized aluminum offers greater adhesion for adhesives and primers. This is because the oxide surface of anodized aluminum has deeper pores that of standard aluminum. The pores are essentially holes in which adhesive, primers or liquids will flow when applied to the surface. As the anodized aluminum soaks up the liquids, it allows for greater adhesion.

Types of Anodize

Type I Class 1 & 2

Chromic Anodize, produces a thinner film than Type II and Type III Anodizing (hard coat) and produces enhanced drawing and forming characteristics. Chromic acid anodizing is used for flight-critical aluminum components that are subjected to high stresses, such as landing gear. Type I Chromic Acid Anodizing works best on aluminum with few alloying elements

Type II Class 1 & 2

Type II anodizing is a process done by placing the aluminum in a sulfuric bath which builds up the aluminum oxide on the surface as well as into the aluminum material too, about half and half. Creates an interesting property of the aluminum oxide making it a great electrical insulator. This dielectric property as a result of anodizing will.

This oxide layer can also be dyed into various colors giving the end product excellent decorative finish options in addition to preventing conductivity and protecting against corrosion. Type II anodizing is the common referral derived from military standard spec Mil-A-8625

Type III Class 1 &2

Hardcoat Anodize is Type III which is done under more exacting process conditions resulting in a harder, denser, thicker, and more abrasion resistant coating. Hardcoat thicknesses can vary from 0.0005 to 0.0030” and beyond but is dependent on the specific alloy being anodized.

Increased abrasion resistance (best when unsealed)

Increased wear resistance Increased corrosion resistance (best when sealed) Improved aesthetics

Dielectric properties (coating is an electrical insulator)

Improved lubrication (particularly when PTFE sealed)

Readily sterilized, non-contaminating (for medical instrumentation)

In Arnolds Metal finishing we can help you with all of your anodize projects.