How To Do Anodizing Aluminum Finishing Creatingway
Anodizing aluminium is an electrochemical process which is greatly advantageous in several ways. There types of anodizing, so you can use the one which fulfills your requirements. When you will learn the process of anodizing, you can be able to do it on your own. Creatingway shares more these information to you today.
Below are the advantages of anodizing aluminum finishing
- Anodizing enhances the durability of the metal as it is protected from rusting
- Apart from durability, the appearance of the metal becomes better as it does shine.
- An anodized aluminium is on demand in the market.
Types of Anodizing Aluminum Finishing
- Hard Anodizing
- Common Anodizing
Hard anodizing is very similar to sulphuric acid anodizing but produces a thicker oxide layer and therefore increased corrosion resistance and
increased wear resistance compared to standard (common) sulphuric anodizing. Hard anodizing sometimes is referred to as hard coat. A thickness of 20 to 70 nano-meter can be achieved with this process.
Below are common anodizing aluminum finishing process
The materials needed in anodizing include; power supply, plastic tub,degreaser product, clothe,sodium hydroxide,sulphuric acid, power supply,a distilled water, dye, lead cathodes and aluminium metal.
Below are more step process for anodizing aluminum finishing
You can use another kind of acid like chromic acid, but sulphuric acid works well for me. It’s better to use little acid at first and add much more acid later slowly than taking it away from the tub. This idea is essential as it will have an impact in increase of the current and its density
This part should be greater in the surface area than the parts you are anodizing. It’s better to use aluminium rotors and aluminium wire to connect to the tank, and they need to be cleaned regularly.
- Power Supply
A controlled power supply is needed. I use a variable power supply of 3 amps. This is able to anodize 2 or 3 160mm rotors. It’s good to leave the voltage constant at 14.5v or basing on your needs.
- The Real Process
Prior to anodizing the metal is cleaned with hot water. If you need a surface etching, put the aluminium for one minute or less in the sodium hydroxide solution, may be with an additive like anadol . Then it should be cleaned with distilled water to remove residues made from etching. The anodized coating is made by passing direct current through sulphuric acid with the anochrome case acting as the anode. After prepare the anodizing bath by getting a plastic tub and put there the acid, anode and cathode. To control the spills during the process use a thick cloth under the tub. Put the aluminium in the electrolyte while making sure it soaks well and you can take it out later may be using a wire tied around it. supply power when everything is set. provide heat of around 37 to 67 degree Celsius. The anodized coating is made when current passes through the electrolyte. To remove the metal part first switch of the power being supplied.
- Dye and Colors
The anodized metal is left porous after using sulphuric acid, hence making it very easy to dye. Here, you have a choice over the colors to use, though you can be limited by the choice of alloy and, hard anodized film tend to be grey in color which limits you much more.
The dye should be heated up to 140 degrees Celsius as you maintain the ph very low.
This can be done in three ways:
- The first method is called cold sealing: The nickel solution is added in the pores of the metal, it’s benefit is that it does not require heating compared to the second method.
- The second method uses hot sodium or potassium dichromate seal, though it leaves a yellowish color on the metal. So you bear in my mind about the final color you want.
- The last method is converting the oxides into hydrated form, the resultant swelling fills the pores. Its disadvantage is that it reduces the abrasion resistance.
How to Compare Anodize and Alodine finishing
It’s good to know the difference between the two. Alodine is a trade name for chemical conversion coating of aluminium. While both are conversion coatings, alodine is much thinner than anodizing and is also created by immersion but without use of electrical current.
Though anodizing takes time, energy and money but it’s worth it. Because the end product being produced will last long, therefore it’s important to get Knowledge of preventing corrosion. The acid and other materials being used are essential and it’s better to know the best materials to use and how to use them effectively. Products which are durable are on a high demand in the market, therefore anodizing aluminium products makes them marketable. Anodizing is also an environmental friendly process, since it does not include heavy metals, halogens or volatiles.
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