Close popup
Request A Quote Email us at [email protected] or fill out the form below to receive a customized quote. *Required Information For Accurate Quote
Max. file size: 100 MB.

Drag & Drop or Choose File to Upload

Anodizing

Anodizing is a specialized electrochemical process that enhances the surface of metals, particularly aluminum, by creating a protective and decorative oxide film. Through controlled oxidation, this process transforms the Aluminums outermost layer into a durable, corrosion-resistant finish, without altering its natural texture and finish. The resulting oxide layer is porous, allowing for dyeing in a wide array of vibrant colors, or it can remain in its natural form. Anodizing not only strengthens the material but also add aesthetic versatility, making it ideal for everything from Aerospace, Commercial Aircraft, to everyday electronics.

Type II anodizing is a versatile electrochemical process that creates a protective aluminum oxide layer on the surface of aluminum, enhancing its durability and corrosion resistance. Within this process, two classifications exist: Class 1 and Class 2. Class 1 anodizing refers to non-dyed finishes, where the aluminum’s natural metallic sheen is preserved, producing a sleek, clear, or slightly tinted surface that offers protection while maintaining the Material’s original appearance. Class 2 anodizing, on the other hand, involves dyeing the porous, unsealed oxide layer, allowing the aluminum to take on vibrant, rich colors while retaining its protective qualities. This makes it ideal for applications where both aesthetics and durability are key, such as in Consumer Products, Commercial Aircraft, and Aerospace. Both classes ensure a durable, corrosion-resistant finish.

Type III anodizing, also known as Hard Anodize, is a more intensive electrochemical process that creates an exceptionally thick and durable aluminum oxide layer on the aluminum surface. Unlike Type II, Type III is performed in a colder sulfuric acid bath with higher voltage, resulting in a denser, harder oxide layer that can withstand extreme wear and abrasion. This makes it ideal for high-performance and industrial applications like aerospace components, military equipment, and heavy-duty machinery. In Type III hard anodizing, class 1 refers to non-dyed finishes, leaving the aluminum in its natural state with a dark, metallic sheen. Class 2 involves dyeing the oxide layer, through color options are more limited due to the density of the coating, typically resulting in darker, mute tones. Both Class 1 and Class 2 hard anodize finishes oƯer superior corrosion resistance and extreme hardness, making them perfect for environments that demand strength, durability, and longevity.

Type 1C, also referred to as A, is an advanced electrochemical process designed primarily for aerospace and military applications. It serves as an environmentally safer alternative to chromic acid anodizing (Type I) while still providing excellent corrosion resistance and a reliable bonding surface for adhesives and coatings. In this process, aluminum in immersed in a bath of boric and sulfuric acids, where an electric current generates a protective aluminum oxide layer on the surface.

The resulting oxide layer is thinner and more flexible compared to Type III anodizing, making it ideal for applications that require minimal material buildup but high resistance to corrosion, such as aircraft components and critical structural parts. While the process does not typically involve dyeing, it ensures strong adhesion and robust durability in harsh environments. Its compatibility with tight tolerances makes it a popular choice for parts where precision and protection are equally critical.

Request a quote

SERVICES

SERVICES

Request a quote

Frequently Asked Questions

  • anodizing Finishes offered at electolurgy:
    • Type II Sulfuric Acid Anodizing (clear & dyed)
    • Type II B Thin Film Sulfuric Acid Anodizing
    • Type III Hard Anodizing
    • Hard Anodizing/Teflon® Seal
    • Selective Masking for Multiple Finishes (such as chem film and type II on the same part)
  • PROPERTIES OF ALUMINUM ANODIZING:
    • Corrosion Resistance: The aluminum oxide film is resistant to atmospheric and saltwater environments.
    • Electrical Insulation: Aluminum oxide film is dielectric.
    • Paint Adhesion: Aluminum oxide film is a chemically active surface for painting.
    • Adhesive Bonding: Aluminum oxide film improves adhesion and bond strength.
    • Cleanability: Anodized coatings do withstand the hydrogen peroxide commonly used in medical sterilization (currently, Electrolurgy offers only clear or black Type II for this application).

    Download our free PDF on Engineering Considerations For Anodizing Aluminum.

  • Anodizing and chemical Film:

    HARD ANODIZING (MIL-A-8625 TYPE III)

    Hard anodizing, often called “Type III Anodizing” as denoted by the MIL-A-8625 specification, is an electro-chemical process that creates a controlled oxide film on the surface of aluminum. Hard anodizing utilizes sulfuric acid, low bath temperatures, and constant current rectification to achieve a very hard coating (60-70 Rockwell C). Hard anodizing is generally used for applications that need a corrosion, abrasion, or wear resistant coating. The appearance of the coating ranges from light to dark gray, depending on the alloy makeup of the aluminum base material, and it can also be dyed black. Parts can be processed with multiple finishes, such as Hardcoat/Chem Film or Hard Coat/Electroless Nickel Plating.

     

    CHEMICAL FILM (CHEM-FILM) CONVERSION COATINGS (MIL-DTL-5541F)

    Chem Film, sometimes called Alodine or Iridite, is a chemical conversion coating that is used to essentially passivate aluminum. It protects aluminum from corrosion and serves as a base for organic (paint) coatings while leaving the part dimensions unchanged. Chem Film is applied by dipping, spraying or brushing. It is sometimes applied alongside Type II Anodizing and can be used to repair minor damage to anodized surfaces. The resultant coating depends on the aluminum condition. Chem film is generally not intended for decorative use and has very little abrasion resistance.

    Chem film per MIL-DTL-5541 Class 3 is electrically conductive. The best corrosion protection is provided by chem film per MIL-DTL-5541 Class 1A. See our ChemFilm Page for more detailed information.

Take Your Business To new heights.

Request a quote
REQUEST A QUOTE