The Challenges For Anodizing Die-Casting Aluminum Parts


Commonly used for aluminum, anodizing is an electrochemical process by which a protective layer creates on the surface of the treated metal, capable of protecting it from corrosive agents.As well as to improve the corrosion resistance, anodization is typically used to increase the surface hardness, and therefore the resistance to wear and abrasion.In other cases it can also be a simple aesthetic choice.

The Challenge For Anodizing Die-Casting Aluminum Parts.

Anodizing requires no impurities on the surface, to ensure that the anodized film must be uniform and smooth. Excessive impurities and other ingredients will affect the thickness of the film formed during anodizing, even it will affects formed or not. Importantly, other metal elements may directly change the color of the film when the anodized film is formed, which is very disadvantageous to the dyeing after anodizing.

It generally has high silicon content for aluminum or aluminum alloy die casting parts.Even use HT412 the special ash-removing reagent for die casting aluminum, the anodized film may also be dark. It is difficult to obtain a colorless, transparent anodized film. As the silicon content increases, the color of the anodized film ranges from light gray to dark gray, then to black gray.

To aluminum alloy parts, anodizing and electroplating treatment are not recommended. That's because gas mark, cold lap, sand hole are easy to occur on the surface of aluminum alloy die casting parts. If anodizing need, it's suggested to change to an aluminum-extruded material. electroplating material is suggested to Zinc aluminum alloy or zinc alloy.

Our Solution

Polishing of the castings may result in the “high” points of the metal surface being smoothed over resulting in “voids” in the metal that may be revealed in the anodizing process. You will have to experiment to see what polishing techniques produce the best finish after anodizing.With years of experience, We KinTec has studied out the best solution to anodizing die casting aluminum.

Anodizing Process For Die-Casting Aluminum
Processing Notices
Deoiling Deoiling-Washing-Drying
Clean Silica Fume 1.Black ash on the surface of the product after deoiling, clean it twice with desilication reagent ES-120, no washing in the two times.
Anodizing 1.Best additive : ordinary temperature hard anodizing additive EC-N, oxidation tank cleaner
3.Pre-coloring: anti-discoloration agent EC-160
Deashing 1.Some black ash after anodizing, clean with:
Decontamination reagent ES-220 :50%
Desilication reagent ES-120 :50%
Temp: ordinary temperature hard
Time: depending on the ash result
2.Soak in the water in 1-2min, washing
Dyeing 1.Black (Deep Black 801, Deep Black 804 & Deep Black 809)
High Temperature Sealing 1, Used Heat sealed salt SE-800 add ed with anti-ash agent ED-58 for best results. If saline-alkali corrosion resistance is required. Use Medium temperature sealant SY-3
2. Ordinary temperature sealed salt EC-3 if dyed no need



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