Aluminium Anodising: Tips to Improve the Quality of the Finish

2 April 2018
 Categories: , Blog


When working with aluminium metal, anodising it is an essential step when finishing the surface. It improves the corrosion resistance properties of the metal, and as a result, your finished product can last for decades even when exposed to moisture and corrosives. Before anodising aluminium, it is critical to remain aware of the factors that can affect the quality of the anodic oxide finish and reduce the durability of the metal. This way, you can take measures to ensure that the finished product has a high-quality, visually appealing and corrosion-resistant finish. Here are some of the key things that you need to take into consideration when anodising aluminium.

Choose quality alloys

There are various types of aluminium alloys, but not all are best suited for anodising. Some alloys have lower corrosion-resistance, low strength and an unappealing surface finish. When anodised, such metals may not deliver a decorative and durable surface finish. As you choose the best aluminium alloy to work with, make sure that it has a high resistance to corrosion, has impressive strength, and the surface finish is attractive. When transformed into an anodic oxide, the properties of the metal alloy will be dramatically improved, and this will increase the durability of your product.

Prepare surface adequately

Aluminium parts are exposed to various surface contaminants in a machine shop. If the metal isn't prepared properly before anodising, it will not acquire a thick protective oxide layer. That's because the contaminants will prevent the oxide from bonding properly to the metal during the electrochemical process. To avoid this, take the right measures to clean and prepare the surface for anodising. Preparation should be done in a controlled environment to avoid further exposure to surface pollutants after cleaning and polishing.

Maintain a controlled environment

Before anodising, aluminium is cleaned and pre-treated. After that, the metal is immersed in an electrolyte solution together with a cathode. An electric current is passed through the solution, and it triggers the release of hydrogen from the cathode. As a result, oxygen forms on the aluminium and creates an oxide layer on the metal. For this process to proceed successfully, it should be carried out in a controlled environment. Regulate the temperature, pH, and time before and after anodising. You can use chemical management tools to determine the ideal ranges for these parameters.

Aluminium anodising requires careful preparation before and after the electrochemical process if you want a part with high corrosion resistance. Follow these tips during the treatment to achieve high-quality and durable anodic oxide finishes.