The anodic finish is the result of the carefully controlled electrochemical oxidation of the aluminum surface. There are numerous types of anodic finishes. Each finish is specified to obtain certain appearance and/or performance characteristics desired according to the end use of the product. Some of the characteristics of anodized finishes are:

• decorative
• abrasion resistant
• reflective
• dielectric
• corrosion resistant
• color
• absorption/emissivity of heat.

Coating thickness is an important attribute of every type of anodized finish. It may be specified as either coating thickness or coating weight, or both. Common units of measurement are:

• inches,
• mils,
• microns, where 1.0 mil equals 0.001 inch (one mil = one one-thousandth of an inch); 25 microns equals 1.0 mil; or 1 micron equals 0.00004 inches.

Coating weight, or mass per unit area, may be stated as mg/cm2 (milligrams per square centimeter), mg/dm2 (milligrams per square decimeter) or mg/ft2 (milligrams per square foot). There are both processing and testing specifications that call out coating weight in these terms.

The most commonly used anodizing process is sulfuric acid anodizing. It produces a colorless, transparent anodic coating on most aluminum alloys. It may be specified in different coating thicknesses to satisfy different functions.