Techmetals, Inc.

Anodized Aluminum

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.

Aluminum Anodize

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:

Anodize Properties:

  • Type II – Used for Corrosion Protection
  • Type III – Extremely Hard, Abrasion Resistant
  • May be Selectively Plated
  • Good Dielectric Qualities
  • Economical
  • Can be Dyed in a Number of Colors

Anodize Industry Specs:

MIL-A-8625 (Types II and III)
AMS 2469
AMS 2471
AMS 2472
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

Sulfuric Acid Anodize
(MIL-A-8625) – Type II

  • Corrosion Resistance and
    provides good abrasion resistance
  • Variety of colors: Red, Fire Red, Blue, Black, Olive Drab Tan, Gold, Blue Grey, and Grey. (*Other colors can be added)
  • Adds durability

Hard Coat Anodize
(MIL-A-8625) – Type III

  • Improved wear resistance
  • Non-conductive
  • Can repair worn surfaces on aluminum
  • Improve parts surface for slide applications
  • Can be dyed; however, does not yield a decorative coat
  • Finish is harder than tool steel
  • Can be ground or lapped

Techmetals Engineered Anodized Aluminum Finishes


oxytechMore than just hard coat anodize, this rigid process delivers a Type III anodize finish that is not only more consistent — but also proven to outwear standard hard coat anodize finishes.


The same superior hard coat anodize finish as OxyTech, with the added lubricity. We have taken sub-micron particles of PTFE and impregnated them into the coating for added wear and lubricity.