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The Difference Between Sandblasting and Anodic Oxidation

212   |   Published by VMT at Aug 17 2021

After the aluminum profile is extruded and formed, it is processed by numerical control. In order to achieve the durability and aesthetics of the parts, the surface treatment will be performed after the processing is fully inspected. Common surface treatments for parts include anodic oxidation, sandblasting oxidation, electrostatic powder spraying and so on.


It is suitable for a variety of materials, different materials, and different surface treatment methods. VMT will choose the appropriate surface treatment for you according to the purpose and material of your processed parts. Each processing technology has its advantages and disadvantages, so what is the difference between the two surface treatment processes of anodizing and sandblasting?





What is anodizing?



Anodizing is an electrolytic process that deposits a chemically stable oxide layer on the surface of aluminum parts. The resulting oxide film is thicker and stronger than the natural oxide coating of aluminum. It is hard, porous, and transparent, and is an indispensable part of the metal surface, so it will not peel or peel off.



The Difference Between Sandblasting and Anodic Oxidation-1




What is sandblasting?




The process of using the impact of high-speed sand flow to clean and roughen the surface of parts. Compressed air is used as the power to form a high-speed jet beam to spray the spray material (copper ore, quartz sand, emery sand, iron sand, Hainan sand) on the surface of the parts to be treated at a high speed, so that the appearance or shape of the part surface will change.

The impact and cutting action on the surface of the part can make the surface of the part obtain cleanliness and different roughness, improve the mechanical properties of the surface of the part, improve the fatigue resistance of the part, and increase the adhesion between the part and the coating. , It prolongs the durability of the coating film, and is also conducive to the leveling and decoration of the coating.





The difference between sandblasting and anodic oxidation




(1) Processing technology:

Sand blasting relies on external force to spray sand to the surface of the parts to achieve passivation treatment, cleaning, decorative design and other practical effects. External force is called dry sand blasting when air is compressed, and wet sand blasting when it is water.



Anodizing generally refers to the oxidation of aluminum and aluminum alloy profiles in hydrochloric acid or other aqueous solutions, the parts are anodicized, and the aluminum alloy plate or graphite plate is connected to the negative electrode. Through the DC power supply, a porous structure, high strength, and dielectric can be obtained. Strong oxide film.




(2) The difference between sandblasting oxidation and anodic oxidation:



1. Different processing methods

Sandblasting of aluminum profiles is a physical treatment, and anodizing of aluminum profiles is a chemical treatment. Generally speaking, if the aluminum profile cannot be anti-corrosive after anodizing treatment, then it needs to be sandblasted and oxidized, and then sprayed, so that it can achieve the expected purpose.


2. Solve the difference in actual effect

Sandblasting and oxidation of aluminum profiles can be cleaned, polished, burrs, and the surface roughness can be changed to achieve practical decorative effects. Anodizing of aluminum profiles does not have this practical effect.


3. Different corrosion resistance
There is no protective layer on the sandblasted and oxidized surface of aluminum profiles, which cannot meet the requirements of corrosion resistance. The anodizing of aluminum profiles can meet the anti-corrosion requirements, and sandblasting must be done before anodizing.




In conclusion


Sandblasting is to achieve the practical effects of passivation treatment, cleaning, decorative design, etc., while anodic oxidation is carried out in hydrochloric acid or other aqueous solutions. The two processes are different in method, effect and corrosiveness.






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