Hard Coat Anodizing (Type III)

Arrow Cryogenics Aluminum HardCoat Anodizing Meets Military Standard Specifications:

• MIL-A-8625 Type III Class 1 (Non-Dyed) and Class 2 (Dyed)

Arrow Cryogenics' offers aluminum hard coat aluminum anodizing (Type III) at our state of the art building in Blaine Minnesota. We also provide standard aluminum anodizing (Type II) services.

What is Hard Coat Anodizing?

Aluminum Hard Coat Anodizing is similar to standard anodizing in that it is also a controlled electrochemical process. The main difference is that Hardcoat Anodizing strengthens or adds to the process of standard anodizing. During the hard coat anodizing process, an anodic film is formed by converting the surface into aluminum oxide. This is accomplished by a sulfuric acid bath that is apporoximately 32 degrees F with a density of 23 to 37 amps and the part is submerged for anywhere from 20 minutes to 2 hours which will determine the thickness of the coating. The aluminum oxide that is formed on the surface is uniform, denser, and much harder than natural oxidation.

Benefits of Hard Coat Anodized Aluminum

Hard Coat Anodized Aluminum is used for some of the following reasons:

• Corrosion resistance
• Aesthetics
• Dielectric properties
• Improve lubrication
• Increased wear resistance
• Increased abrasion resistance
• Lightweight
• Flame resistance
• Non-contaminating (Medical instrumentation)

How does hard coat anodizing affect dimensions?

It is important to understand when hard coat anodizing parts with tight dimensions, that the coating will affect the final dimensions. 50% of the coating penetrates into the surface and 50% of the coating builds up on the surface. The final dimension is determined by the thickness of the coating. The thickness of coating is controlled with great accuracy by using state of the art controls. The typical thickness that is required for hard coat anodizing is .002. When setting up a project we make sure that the required specifications are included in the work contract documents. This will ensure that the thickness turns out exactly as expected. We work closely with our customers when tight dimensions are a requirement.

How does hard coat anodizing affect the appearance of aluminum?

In hard coat anodizing, if the aluminum is not dyed (Class I), the color of the aluminum will change. The color of the aluminum after it has been hard coat anodized will depend on the alloy and the thickness of the coating. The color of the aluminum after hard coat anodizing will be gray/bronze on some alloys and gray-black on other alloys. If dyed (Class II), black is the color most commonly used. Other colors may be available depending on the alloy and the coating thickness. If a color other than black is needed, sampling will be required.

Sealing after hard coat anodizing

After a component has been hard coat anodized, it may or may not be sealed. If the main function of the application is to obtain the maximum degree of abrasion or wear resistance the coating should not be sealed. If the main function of the application is for corrosion resistance but permits reduced abrasion resistance sealing may be used. Our customers will need to specify when sealing is required.

These are just a few of the industries that benefit from the standard anodizing and hardcoat anodizing:

To review some of the other finishes, click on the links below:

Straightlining | Abrasive Blasting | Shot Blasting | Vibratory/Tumble Deburring | Thermal Deburring

Arrow Cryogenics is an ISO:9001:2008 certified company.

Please contact us for more information about our aluminum anodizing and hardcoat anodizing services.