Anodizing Services

Anodizing - Improve Performance

Aluminum

Aluminum Alloys

Titanium

Anodizing Service Partners Available

With our partnerships with leading anodizers, ISO Finishing’s anodizing service can match our pre-plating processing with the correct anodizing to provide seamless delivery of your finished products.

Anodizing is an electrolytic passivation process used to increase the thickness of the natural oxide layer on the surface of metal parts. Anodizing increases corrosion and wear resistance and provides better adhesion for most paint primers and glues than bare metal.

Anodization changes the microscopic texture of the surface and changes the crystal structure of the metal near the surface. Thick anodized coatings are normally porous, so a sealing process is often needed to achieve corrosion resistance. Anodized aluminum surfaces are harder than the aluminum they cover but have low to moderate wear resistance. This wear resistance can be improved with increasing thickness or by applying suitable sealing substances during the anodizing process. Anodic films are generally much stronger and more adherent than most types of paint and metal plating, but also more brittle. This makes them less likely to crack and peel from aging and wear, but more susceptible to cracking from thermal stress.

Anodic films can also be used for a number of cosmetic effects, either with thick porous coatings that can absorb dyes in any number of colors or with thin transparent coatings that add interference effects to reflected light. Anodic films are most commonly applied to protect aluminum alloys. However, processes also exist for titanium, zinc, magnesium, niobium, zirconium, hafnium, and tantalum.

Contact ISO Finishing today for more information about we can help with your anodizing requirements.

Benefits of Anodizing

ISO Finishing offers anodizing through vendor partnerships:

• Aesthetics
• Bonding
• Corrosion Resistance

• Heat Dissipation

• Lubricity
• Wear Resistance

Types of Anodizing

Chromic Acid Anodize

Type I or chromic acid anodizing is used primarily by our aerospace customers in precision applications, as it is the thinnest form of anodizing and does not appreciably change a part’s dimensions. Chromic acid anodizing can be used for inspection of aluminum forgings or castings by noting evidence of chromic acid bleed out from laps, cracks, seams, etc. The resulting color from chromic acid anodizing will vary from light gray to dark gray depending on the alloy. Type 1 is not as readily dyed as sulfuric anodize.

Chromic Acid Anodize Features:

  • Good for tight tolerance parts: will not change dimensions
  • Can be black dyed – other colors not practical
  • Good for Bonding
  • Non-Conductive
  • Good for welded parts and assemblies

Chromic Acid Anodize Applications:

  • Precision Machined Components
  • Aerospace Components
  • Welded components and assemblies
  • As a paint/prime base

Sulfuric Acid Anodize – Type II

Type II aluminum anodizing is performed using a sulfuric acid bath to create the anodic aluminum oxide surface. This method is often referred to as “conventional anodizing” for good reason. Type II anodizing is very versatile and provides an ideal surface for dye application. The resulting color will vary with alloy composition. Aluminum with low alloying elements will show practically no color change. This means Type II can be dyed practically any color or shade (black, blue, red, gold, orange, green etc.)

Boric-Sulfuric Acid Anodize Features:

  • Good for tight tolerance parts: will not change dimensions
  • Corrosion protection
  • Good for Bonding
  • Non-Conductive

Boric-Sulfuric Acid Anodize Applications:

  • Precision Machined Components
  • Aerospace/Aircraft Components
  • As a paint/prime base

Sulfuric Acid Anodize – Type III

Type III sulfuric acid anodizing is commonly referred to as “hardcoat anodizing” as it is used to protect aluminum parts in harsh wear applications. Hardcoat anodizing creates a denser anodized layer that may reach up to 0.002″ in thickness. Type III is dyed easiest of all because of the deep pores created. The hardcoat process darkens and alters the base metal enough so that the color is dramatically different than Type II, i.e. red dye on Type II is fire engine red while on Type III it is dark burgundy.

Sulfuric Acid Anodize Benefits:

  • Less expensive than other types of Anodize with respect to chemicals used, heating, power consumption, and length of time to obtain required thickness.
  • More alloys can be finished.
  • Harder than chromic anodize.
  • Clearer finish permits dying with a greater variety of colors.

Sulfuric Acid Anodize Applications:

  • Optical components
  • Hydraulic valve bodies
  • Military weapons
  • Computer and electronic enclosures
  • Mechanical hardware

Hard Anodize (Hardcoat):

Hardcoat anodize, while usually done in a sulfuric acid based electrolyte, is much thicker and denser than the more conventional sulfuric anodize. Hardcoat is specified for aluminum components subject to extreme wear applications where superior abrasion resistance is needed, or corrosive environments where a thicker, harder, more durable coating is necessary. It can also be valuable where enhanced electrical insulation is required. Since hardcoat anodize can be built up to several thousandths in some cases, it makes this type of anodize a candidate for salvaging worn or mis-machined components.

Hard Anodize Features:

  • Improved wear resistance
  • Non-conductive
  • Can repair worn surfaces on aluminum
  • Improve parts surface for slide applications
  • Can be black dyed; other colors less decorative
  • Finish is harder than tool steel

Hard Anodize Applications:

  • Valves
  • Pistons
  • Sliding Parts
  • Hinge Mechanisms
  • Cams
  • Gears
  • Swivel Joints

Titanium Anodize:

Titanium Anodize refers to the controlled creation of an oxide film on the surface of titanium parts. Titanium anodize is used for many reasons, from part identification in the medical device community, to corrosion control and bonding in the aerospace community. Depending on the grade of titanium alloy, it can be anodized many different colors.

Titanium Anodize Features:

  • Used for coloring of titanium
  • Used to aid in looking for stress cracks in base material
  • Improved corrosion resistance
  • Improve adhesion of dry film lubricant or paint application

Titanium Anodize Applications:

  • Aircraft parts
  • Medical devices
  • Spacecraft components