The anodizing of aluminum is an electrolytic oxidation process. Aluminum and its alloy in the corresponding electrolyte and specific process conditions, due to the action of external current, the process of forming an oxide film on the aluminum product (anode).
Therefore, if anodizing is not specifically specified, generally speaking, the anode is made of aluminum or aluminum alloy as the anode, the cathode is selected as the lead plate, the aluminum and lead plate together in an aqueous solution, which contains sulfuric acid, oxalic acid, chromic acid, etc., for electrolysis, so that the surface of the aluminum and lead plate forms an oxide film.
Among these acids, the most widely used is anodizing with sulfuric acid.
01. Improve corrosion resistance
In fact, aluminum alloy is a corrosion-resistant metal, because aluminum is very active, especially easy to chemically react with oxygen in the air to produce alumina.
The alumina film is transparent, so it is difficult for the human eye to see. This thin alumina film just keeps the air out so that the aluminum substrate is not oxidized. That's why it's corrosion-resistant.
So naturally generated oxide film can play an antioxidant role, why also need anodizing?
1, the naturally formed oxide film is not uniform, resulting in different color shades on the surface of aluminum alloy, more ugly;
2, the naturally formed oxide film is very thin, easy to be scratched, corrosion resistance is relatively weak. The artificial oxide film produced by anodic oxidation is uniform, dense and more corrosion resistant.
02. Improve wear resistance
Aluminum profile substrate is particularly easy to scratch and wear, aluminum alloy hardness can not be compared with steel after all.
The surface of the anodized industrial aluminum profile is very hard, and the oxide film has high hardness. Therefore, after anodizing, it is very wear-resistant and not easy to scratch.
Before aluminum anodizing sealing, there will be a lot of dense pores on the surface, which is easy to absorb some metal salts or dyes, so that the surface of aluminum products form colorful colors.
04. Improve insulation
The electrical conductivity of aluminum is very good, but aluminum needs insulation in some cases. Anodized aluminum oxide film is not conductive, so if you need to use insulation occasions need to anodize.
05. Base the spray paint
The surface of some aluminum parts needs painting treatment, and the surface gap of the aluminum parts after anodizing has strong adsorption, so that the painting is more uniform and beautiful.
The combination of aluminum alloy and anodizing process has so many advantages that the anodized aluminum alloy is widely used in our lives.