Aluminum anodizing is an electrochemical process that converts aluminum into a durable, corrosion resistant, anodic oxide finish.
The metal substrate is considered the “anode” in this electrolytic process, which is why we use the term anodizing. An electrical current is passed between the metal and a cathode – usually flat, aluminum bars in a sulfuric acid bath – producing an anodic oxide.
This aluminum oxide is not applied to the surface like paint or plating, but is fully integrated with the underlying aluminum substrate, so it cannot chip or peel. It has a highly ordered, porous structure that allows for secondary processes such as coloring and sealing. Anodizing is, therefore, a matter of highly controlled oxidation — the enhancement of a naturally occurring phenomenon.
Anodized finishes have made aluminum one of the most respected and widely used materials today in the production of thousands of consumer, commercial and industrial products.
The anodized aluminum coating thickness penetrates 50% into the surface of the substrate and 50% on the surface where there is some growth. (i.e. coating thickness of .001″ per side will grow by .0005″ per side or surface)
Benefits of Anodizing:
- Type II – Used for Corrosion Protection
- Type III – Extremely Hard, Abrasion Resistant
- May be Selectively Plated
- Good Dielectric Qualities
- Can be Dyed in a Number of Colors
Anodize Industry Specs:
MIL-A-8625 (Types II and III)
ASTM B 580
Medical Validated Lines/Processes
— Type II: .0001-.001
— Type III: .0016-.0024
Can apply from .0001 – .0004 total thickness
>336 hours per ASTM B-117
1000V per .001″ coating thickness
On-line dyes consist of black, red, blue, olive drab, tan, blue grey and others; specific dye needs can be satisfied upon request
Hot Water Seal, Nickel Acetate, Sodium Dichromate