T-slotted aluminum extrusions come in a variety of finishes and are capable of withstanding almost any environment they are installed in. The most common t-slot finishes you will see are the standard aluminum (silver), anodized black, or safety yellow. Of the three, anodized black t-slot has grown in popularity for various types of applications, including:
- Tables and Utility Carts
- Aquarium Stands
- Solar Panel Racks
- Lean Solutions
No matter the application, anodized black t-slot profiles provide a sleek and stylish finish to a design. But what exactly does anodize mean? Below we will answer that question and more and provide helpful tips when ordering black anodized t-slot.
Anodizing: What is It?
Anodizing transforms the metallic surface of aluminum through an electrochemical process. This process provides an anodic oxide finish that is attractive, hard-wearing, and corrosion-resistant.
The anodizing allows the surface to become more porous and capable of receiving the black pigment. Anodized aluminum extrusions are highly durable and require minimal maintenance, just like standard extrusions. The only difference is the finish.
Anodizing is environmentally sound and does not cause adverse effects to the land, air, or water. The only other material with a more rigid crystalline structure than anodized aluminum is a diamond.
How is Aluminum Anodized?
Aluminum is prepared for anodizing by first being cleaned and rinsed thoroughly. Once cleaned, it is placed in an electrolytic solution bath along with metal plates. This electrically conductive solution made of electrolytes has many positive and negative ions looking to be swapped. To achieve this swap, the aluminum has a positive electric charge applied to it, while the plates have a negative charge applied to it.
While submerged, the aluminum will form pores from the electrochemical reaction. The pores are caused by positive ions escaping and forming a geometrically regular pattern that erodes the surface. At the surface, the aluminum combines with the O2 ions (negatively charged) to create aluminum oxide. This is called the barrier layer. The barrier layer will defend against any further surface oxidation.
As current continues to be applied, the pores will run deeper, forming hollow columns. The greater the current, the deeper the columns. The depth for typical non-hard coatings is up to 10 microns. Once this level is reached color is added, the surface is sealed with a water rinse. This aluminum oxide coating will leave a surface that rates a 9 out of 10 on the Mohs hardness scale.
Color: How is it Added?
With stable pores etched into the aluminum, color can be added electrolytically by means of a metal salt solution. The metal oxides that have been embedded in the anodized layer produce lightfast shades in the pores. Pigments added to anodized aluminum cannot be scratched off due to the depth that they travel.
What is Hard-Anodizing?
This is often called Type III and offers a greater level of protection against corrosion and wear. To produce hard-anodized aluminum, the current is continued until the depths of the pores exceed 10 microns up to 25 microns or greater. This extension of the process is more time-consuming and expensive but produces a superior result.
Heat Dissipation: Does Anodizing Improve It?
Anodizing aluminum does help with heat dissipation. Anodized aluminum has a greater surface area than unfinished aluminum, so when radiative heat transfer (emissivity) occurs, anodized aluminum will dissipate the heat dramatically.
Will Anodizing Affect the Strength of the Aluminum?
The electrochemical process only affects a small layer of the aluminum’s surface. To put this into perspective regarding measurement, it’s the difference of nanometers. The bulk of the material and its capabilities remains unchanged.
Should You Anodize Your Aluminum T-Slot Extrusions?
Depending upon the application, anodizing t-slot aluminum can be helpful with the following:
- Improving Emissivity
- Corrosion Resistance
If any of the above is something you are looking to achieve in your application, then anodizing will be preferred. Alternatives to anodizing are powder coating and PVDF coating.
Helpful Tips for Ordering Black Anodized Aluminum
When ordering black or yellow aluminum t-slot, it is essential to note that all areas that are machined, cut, counterbore, etc., will be exposed. To be exposed means that there will be no coloring in these areas.
If you do not want exposed uncolored areas on your t-slot, you will need to choose full-color extrusions. Full color generally takes a little longer because most companies will need to send it out.
To learn more about black anodized t-slot and what it can be used for, register and check out our forum.