ANODIZING

Anodizing at PAIMEX

Anodizing converts the surface of aluminum into a film of aluminum oxide (Al₂O₃), known as alumina, through a controlled electrolytic reaction.

The result is a thicker, harder, and more durable layer. It is uniform, adherent, and highly resistant, providing corrosion protection, improving surface hardness, and delivering a homogeneous appearance across the entire surface.

An important property of anodizing is that the alumina layer is dielectric, which means it does not conduct electricity. While the aluminum beneath remains conductive, the anodized surface becomes an electrical insulator. For applications requiring electrical contact, specific areas must be masked prior to anodizing to keep conductive zones.

In this process, alumina forms directly on the part’s surface, becoming a protective barrier that extends service life and enhances performance under demanding conditions.

In addition to the natural aluminum color, the process allows for controlled coloring to meet both aesthetic and functional requirements.

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Key benefits

Protection

Corrosion resistance

The anodic layer protects effectively in humid and aggressive environments, preserving part integrity.

Durability

Greater wear resistance

Increases surface hardness and extends service life against friction and abrasion.

Aesthetics

Uniform, controlled color

Natural or colored finish with excellent lot-to-lot repeatability.

Functional

Electrical insulation & anchor base

Alumina is dielectric and improves the adhesion of paints, adhesives, and sealants.

How it works: controlled electrolytic reaction

Preparation: cleaning and degreasing to ensure a contaminant-free surface.
Electrolytic cell: the part is connected as the anode and immersed in the electrolyte; an opposing cathode completes the circuit.
Current application: oxygen ions react with aluminum to form an adherent, uniform film of Al₂O₃.
Parameter control: voltage, time, temperature, and concentration determine layer thickness and microstructure.
Sealing and/or coloring: as required, to maximize corrosion resistance and color stability.

Anodizing at PAIMEX — Alumina formation through anodizing

Anodizing types we offer

Type I (Chromic acid)

Thin film with excellent compatibility with adhesives and high corrosion resistance. Common in aerospace.

Type II (Sulfuric acid)

Versatile for decorative and industrial applications. Enables uniform coloring and consistent finishes.

Type III (Hard Coat)

Thicker, harder coating for parts exposed to heavy wear, friction, and severe loads.

Color options

In addition to a natural finish, PAIMEX offers color application on parts. These finishes can also be carried out through co-development with the customer to create a specific color or finish tailored to your needs. Availability depends on requested requirements as well as part shape and size.

Industries & certifications

PAIMEX serves the aerospace, automotive, electronics, medical, telecommunications, and commercial sectors, supported by robust quality systems and third-party audits.

Nadcap Accredited – Chemical Processing
ISO 9001:2015 / AS9100D
We have an in-house laboratory to verify parameters and coating thickness per requirements.

Frequently asked questions

Which materials can be anodized?

The process is designed for aluminum alloys. Compatibility depends on the series and end use—our team can advise based on your part.

How do I define the right thickness?

It depends on service environment, expected friction, and specification requirements. We’ll recommend the optimal range for your application.

Does color affect protection?

Protection comes mainly from thickness and sealing. Color is selected for aesthetics and functional needs.

Anodizing Explained

When we hear the term anodizing, the first thing that comes to mind is that it is a type of paint applied to aluminum. While this has some truth, the reality is that the process itself is a way to protect the material against corrosion caused by atmospheric agents, as well as wear and tear that the anodized parts or pieces will be subjected to.

Through the anodizing process, an artificial film of aluminum oxide of a certain thickness known as alumina is obtained. This has the main characteristic of providing greater protection than other coatings as a result of the chemical and electrolytic processes involved in the procedure.

Anodizing can achieve a natural color of aluminum or any other color.

Types of Anodizing

Chromic Anodizing

Specification: MIL-A-8625 / AMS-A-8625 / MIL-PRF-8625
Type: IB Low Voltage
Class: 1 no dyed (sin color)
Coating Thickness

inch0.00002 – 0.00070

µm0.508 – 17.78

mils0.02 – 0.70

Sulfuric Anodizing

Specification: MIL-A-8625 / AMS-A-8625 / MIL-PRF-8625
Type: II
Class 1: no dyed (sin color)
Class 2: dyed (con color)
Coating Thickness

inch0.00007 – 0.0010

µm1.778 – 25.4

mils0.07 – 1.00

Hard Anodizing

Specification: MIL-A-8625 / AMS-A-8625 / MIL-PRF-8625
Type: III
Class: 1 no dyed (sin color)
Class 2: dyed (con color)
Coating Thickness

inch0.0005 – 0.0045

µm12.7 – 114.3

mils0.5 – 4.5

Anodizing Types We Offer and Their Characteristics

Chromic Anodizing

Specification: MIL-A-8625 / AMS-A-8625 / MIL-PRF-8625
Type: IB (low voltage)
Class 1: Non-dyed (no color)
Coating thickness

in0.00002 – 0.0007

µm0.508 – 17.78

thousandths (mils)0.02 – 0.70

Sulfuric Anodizing

Specification: MIL-A-8625 / AMS-A-8625 / MIL-PRF-8625
Type: II
Class 1: Non-dyed (no color)
Class 2: Dyed (with color)
Coating thickness

in0.00007 – 0.0010

µm1.778 – 25.4

thousandths (mils)0.07 – 1.00

Hardcoat Anodizing

Specification: MIL-A-8625 / AMS-A-8625 / MIL-PRF-8625
Type: III
Class 1: Non-dyed (no color)
Class 2: Dyed (with color)
Coating thickness

in0.0005 – 0.0045

µm12.7 – 114.3

thousandths (mils)0.5 – 4.5

ABOUT PAIMEX

PAIMEX is a company that has been operating since 2005 and is dedicated to offering METAL FINISHING services.

We are based in Mexicali, B.C., Mexico, on the border with Calexico, California; 2 hours from San Diego and 4 hours from Los Angeles, California. Thanks to our location, we are also close to Baja California’s main industrial hubs: Tijuana (~2.5 h), Tecate (~1.5–2 h), Playas de Rosarito (~3 h), and Ensenada (~3.5–4 h).

LOCATION

📍 Address:
José María Rotea #3442, Col. Huertas de La Progreso.
Mexicali, B.C., Mexico.
Zip Code: 21190

☎ Phones:
(+52) 686 555-9156

📧 Email:
info@serviciospaimex.com

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PAIMEX 20th Anniversary: 2005-2025