Applying surface finishing is one of the final steps in manufacturing, but one that’s critical to both the durability and aesthetics of a product. Anodizing colors is part art and part science, resulting in expertly crafted finishes that are as hardy as they are visually striking.
From aerospace components to medical devices and more, color anodizing is indispensable across all industries. As manufacturers and designers increasingly prioritize both functionality and aesthetics in their products, understanding the nuances of anodizing colors matters that much more.
And that’s why working with the right anodizing partner is so important. Anodizing color is not just applying a hue, but rather transforming the metal surfaces with a durable, vibrant finish that withstands the rigors of time and environment.
Here’s what you need to know about anodizing colors and how AOTCO Metal Finishing can support the final stages of your product.
Anodizing is a method of electrolytically enhancing the surface of non-ferrous metal – usually aluminum or titanium alloys. This process not only fortifies the material against corrosion and wear but offers a potential canvas for captivating colors.
Not all anodizing is equal. While all three types of anodizing explained below will improve durability and corrosion resistance, the properties and benefits vary.
Type I Anodizing, also called chromic acid anodizing, is the thinnest of the anodic coating processes. It creates an electrically non-conductive surface with improved scratch and corrosion resistance.
AOTCO specs for Type I Anodizing include:
Type II Anodizing, also known as sulfuric acid anodizing, is the most common method for anodization. It’s used particularly in applications where hardness and resistance to abrasion are needed, or as a base for paint systems.
AOTCO offers both Type II and Type IIB (thin sulfuric acid anodizing) with the following specs:
Type III Anodizing, sometimes called hard anodizing or hard coat anodizing, adds a greater thickness and weight compared to the other two types. It is highly abrasion resistant and non-conductive. In fact, it can make an aluminum surface harder than tool steel.
The following Type III specs are available from AOTCO:
Unlike conventional methods such as painting or powder coating, color anodization brings about a chemical transformation in an object’s surface, rather than simply adding a physical layer of color. The dye is impregnated to the surface of a substrate and then sealed post-anodizing which provides a long-lasting and durable aesthetic finish.
Color anodization can be applied to all three of these anodizing types. However, each type possesses unique characteristics that influence the coloring process because of the formation of pores on the surface of the oxide layer during anodization. These pores vary in their frequency, depth and width, and so interact with dyes in different ways. This results in variations in color intensity and appearance.
In particular, Type III hard coat anodization has more limited dyeing capabilities because of its thicker oxide layer.
Custom colors on anodized aluminum surfaces are not only about aesthetics but functionality, providing visual cues for identification or branding. Here are some of the most popular anodized aluminum colors and their applications:
Aluminum is the prime candidate for anodizing because of how compatible the metal surface is with anodizing and coloring methods. The resulting anodized coatings on aluminum materials provide a layer of protection that is both functional and attractive.
When anodizing aluminum, several techniques and tips ensure optimal results:
While aluminum is the most common material for anodizing, other metals like magnesium and titanium can also undergo a similar electrolytic finishing process to achieve an anodized coating.
Magnesium anodizing takes the naturally occurring oxide layer on the metal’s surface and chemically builds a protective layer on the surface of a magnesium substrate. This greatly improves the anti-corrosion properties, physical strength and adhesion capabilities for dyes. Anodized magnesium has applications in numerous industries including aerospace, defense and medical thanks to its high strength-to-weight ratio, wear resistance and ability to be sterilized.
Similarly, titanium anodizing (Mil Spec AMS 2488) is also often used in aerospace, defense, automotive and medical applications. Titanium anodized parts are biocompatible, resistant to wear and anti-corrosive. Type III anodized titanium in particular offers a range of colors for aesthetic appearance, including silver, bronze, purple, blue, light blue, gold, rose, magenta, teal and green.
The primary difference is the thickness and properties of the oxide layer formed during the anodizing process. Type II anodizing produces a thinner oxide layer that enhances appearance and provides some level of corrosion protection. Type III anodizing, also known as hardcoat anodizing, creates a thicker, denser oxide layer that significantly increases the material's wear and corrosion resistance.
Anodized aluminum colors are remarkably stable due to the dye being sealed within the porous oxide layer. However, prolonged exposure to UV light can cause some colors to fade over time. Red and blue hues are particularly susceptible to fading, while black and darker colors tend to be more UV resistant.
Anodized aluminum is used in a wide range of applications due to its enhanced durability and aesthetic appeal. Common applications include architectural components, consumer electronics, kitchenware, aerospace parts and medical devices.
Anodized aluminum is highly resistant to corrosion, making it a preferred choice for applications where durability and longevity are paramount. The anodizing process creates a protective oxide layer on the surface of the aluminum, which acts as a barrier against corrosion and oxidation. This oxide layer is formed through an electrolytic process that thickens the naturally occurring oxide layer on aluminum, making it harder and more resistant to environmental factors.
Welding anodized aluminum requires removing the anodized layer around the area to be welded, as the oxide layer does not conduct electricity well and can contaminate the weld. After welding, the part can be re-anodized to restore corrosion resistance and aesthetic appearance.
Partnering with AOTCO means gaining access to a trusted team invested in your project's success through delivering results that exceed your expectations. Our team of senior anodizers, platers and engineers have decades of experience providing consistent and quality color anodizing, as well as other metal finishing solutions.
Reach out to us today to learn more about how we can help you achieve your metal finishing goals with confidence and precision.