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Brief introduction

Anodized aluminum or aluminum alloy products are placed in electrolyte solution for galvanization treatment, and the process of forming aluminum oxide film on the surface by electrolysis is called anodized treatment of aluminum and aluminum alloy. After anodic oxidation treatment, aluminum surface can produce several microns — hundreds of microns of oxide film.Compared with the natural oxide film of aluminum alloy, its corrosion resistance, wear resistance and decoration are obviously improved and improved.

Bacial principle

The principle of anodic oxidation of aluminum is essentially the principle of hydroelectrolysis.When an electric current is passed, the following reaction occurs:
At the cathode, H2 is released as follows: 2H + + 2e → H2
At the anode, 4OH-4E → 2H2O + O2, the oxygen precipitated is not only molecular oxygen (O2), but also atomic oxygen (O) and ionic oxygen (O-2), usually expressed as molecular oxygen in the reaction.
As an anode, aluminum is oxidized by the oxygen precipitation on it to form an Al2O3 film without water: 2AI + 3[O] = AI2O3 + 1675.7kj It should be pointed out that not all of the oxygen generated interacts with aluminum, but some of it is precipitated in the form of gas.
Anodic oxidation has long been widely used in industry,such as aluminum CNC machining parts. After anodized, aluminum CNC machining parts can get amazing appearance and good antioxidant capacity.

There are many ways to label different names, which can be summarized as follows:
According to the current type, it can be divided into direct current anodizing, alternating current anodizing, and pulsed current anodizing, which can shorten the production time to reach the required thickness, the film layer is thick and uniform and dense, and the corrosion resistance is significantly improved.
According to the electrolyte: sulfuric acid, oxalic acid, chromic acid, mixed acid and organic sulfonic acid solution of natural coloring anodic oxidation.
According to the properties of the film, it can be divided into ordinary film, hard film (thick film), porcelain film, bright modification layer and barrier layer of semiconductor action.
The anodizing method of direct current electrosulfuric acid is the most popular, because it is suitable for anodizing aluminum and most aluminum alloys.The film layer is thick, hard and wear-resistant, and better corrosion resistance can be obtained after sealing the hole.The film layer is colorless and transparent, with strong adsorption capacity and easy coloring.Low processing voltage, less power consumption;The process does not need to change the voltage cycle, which is conducive to continuous production and practical operation automation;Sulfuric acid is less harmful than chromic acid, wide supply, low price advantages.