Anodizing is a electro-chemical process that produces a oxide coating on an aluminum substrate. The coating formed is an integral part of the substrate and it rises both above and below the original surface. Aluminum oxide is the 3rd hardest element known to mankind, but its characteristics can be influenced by the choice of the electrolyte as well as temperature. Aluminum oxide is a porous coating. The closing of its pores with a chemical such as nickel acetate is referred to as Sealing; whereas the filling of this pore with organic dye or metal to reflect light is called Coloring.
Sulfuric acid anodizing is the most common anodizing process for commercial and industrial products. Its color will vary depending on the alloy, but is generally a opaque gray. It is the best coating on aluminum for dyeing. It can be dyed practically any color. The following is a list of the colors we use for dying: Black, Blue, Gold, Gray, Green, Purple and Red.
|MIL-A-8625 F||.000070 – .001|
|Type II||Use on all aluminum alloys, but do not use where solution will become entrapped.|
|Type IIB||Light coating|
|Class 1||Non-dyed (Clear)|