Question

How is anodizing of aluminum carried out?

Answer 1

Hint : Anodizing is an electrolytic passivation process that is used to increase the thickness of natural oxide layer on metal surface. In other words, anodizing is an electrochemical process that converts the metal surface into decorative, durable, corrosion-resistant anodic oxide finish. The anodic oxide structure originates from an aluminum substrate and is composed of completely aluminum oxide.

Complete Step By Step Answer:
Anodizing is widely used to protect aluminum against corrosion using oxidic protection-layer. Firstly, the aluminum parts are cleaned and pickled using basic and acidic solutions to remove the residues. Then the anodizing process is carried out in an electrolytic bath, commonly containing sulfuric acid. In this process, the products are connected to the anode and hence an oxide layer is built on the surfaces of the parts. Colourization of the products is done afterwards in most of the cases and sealing of new surfaces with hot water finalizes the product.
Process of electrolyte bath monitoring: the bath is where the anodizing is carried out which mainly contains sulfuric acid, aluminum-sulfate and water. To ensure the constant composition of the bath, customer specific acid and salt concentration is continuously monitored and hence a constant high quality of the protective film is guaranteed.

Note :
It is extremely important to be very careful while cleaning anodized aluminum. pH neutral detergents should be used while doing so, because they do not affect the anodized material. The main advantage of anodized aluminum is its low maintenance requirements and can be naturally cleaned by rain. Under extreme conditions, it is recommended to clean the aluminum twice a year.