{"id":9289,"date":"2021-03-02T14:28:17","date_gmt":"2021-03-02T12:28:17","guid":{"rendered":"https:\/\/fractory.com\/?p=9289"},"modified":"2024-06-06T16:56:25","modified_gmt":"2024-06-06T13:56:25","slug":"aluminium-anodising","status":"publish","type":"post","link":"https:\/\/fractory.com\/aluminium-anodising\/","title":{"rendered":"Aluminium Anodising"},"content":{"rendered":"

Aluminium is the second most widely used metal in the world. Engineers prefer aluminium for its light weight, corrosion resistance and reasonable price.<\/p>\n

However, untreated aluminium has low wear resistance. On exposure to the environment, it forms a thin aluminium oxide layer<\/a> naturally that provides aluminium with its characteristic corrosion protection. But this naturally formed oxide film can erode upon reaction with other environmental elements.<\/p>\n

The answer to providing better protection lies with anodising. This procedure has other benefits as we will learn further into the article. But let’s start from the beginning.<\/p>\n

What Is Anodising?<\/strong><\/h2>\n

It is an electrochemical process that develops an aluminium oxide coat on the surface of the part or product. This protects the product from wear and tear while improving the aesthetics. In this process, the product to be coated acts as an anode in an electrolytic cell, hence the name.\u00a0<\/p>\n

On an industrial scale, anodising made its first appearance in 1923.<\/p>\n

Soon, many variations of this process came into use for different materials using various electrolytic chemicals. It was around this time that Gowen and O\u2019Brien used sulfuric acid to anodise aluminium.<\/p>\n

This process from almost a century ago still remains the most common and effective method today.<\/p>\n

Anodised Aluminium Benefits<\/strong><\/h2>\n

The aim of the process is to increase the thickness of aluminium oxide on the surface of the product.<\/p>\n

Aluminium oxide layer is extremely hard. On the Mohr\u2019s scale, it has a score of 9 and is second in hardness only to diamond. It is so hard that it is commonly used as an abrasive in sandpapers. Depositing a layer of this material on the product ensures that the product will have high wear resistance<\/a>.<\/p>\n

The thickness of this layer depends on the purpose of anodising. For decorative purposes, a thin layer is enough. A thicker layer protects the surface besides improving the appearance.<\/p>\n

Having a thick layer of aluminium oxide also makes the metal surface more receptive to dying as pores are created on the surface when it is anodised. Then, desired pigments are introduced that fill the pores from the surface to its very depth. This makes the pigment quite durable as it cannot be scratched away.<\/p>\n

Anodising can also act as an excellent primer for a regular coat of paint on the surface instead of accommodating it into the actual oxide layer.<\/p>\n

Anodising aluminium improves the insulation properties of aluminium as aluminium oxide is not a good conductor of electricity.<\/p>\n

Working Principle<\/strong><\/h2>\n

\"anodizing<\/p>\n

Anodising works on the principle of an electrolytic cell. In this procedure, the anodising tank is filled with a suitable electrolyte. In this tank, the part is usually suspended to expose most of the surface to the electrolyte.<\/p>\n

We then place plates of suitable elements (usually lead or aluminium) in the tank. The next step is completing the circuit between the cathode and anode through a power source.\u00a0<\/p>\n

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