Have you ever wondered about the processes behind treating and finishing certain metals? If you have seen aluminium parts with a tough, durable, and sometimes sleek-looking finish, you may well have been looking at something that has been hard anodised. This process sounds complicated, but it is used widely in applications from cookware to the aerospace industry. Let’s look at hard anodising in more detail.

What is hard anodising?

Simply put, it is a process that strengthens the surface of aluminium. It does this by creating a thick and protective oxide layer; unlike painting or plating, anodising doesn’t sit on top of the metal but changes the surface. Hard anodising creates a tough and corrosion-resistant coating that will help the product survive wear and tear.

How does it work?

Aluminium is submerged in an acid electrolyte bath, which is usually sulphuric acid, and an electric current is passed through it, which causes the substance to oxidise in a controlled way. Compared with other standard anodising methods, hard anodising uses colder temperatures and higher currents for a thicker and harder layer. The coating is dense and can withstand more than coatings made from harder metals, meaning it will do an excellent job of withstanding the weather and lasting through the years.

What can be anodised?

Hard anodising is best used on certain aluminium alloys, such as the 6000 and 7000 series. Not every alloy will be ideal for hard anodising, so it is worth checking before beginning a project; alternatively, you can use a company that specialises in surface treatments, such as www.poeton.co.uk/surface-treatments/anodising/hard-anodising.

Why hard anodising?

There are a few reasons to choose this method. Firstly, it is durable and boosts surface hardness, which is great for any parts that might experience friction or impact. It can resist corrosion and rust, making it great for applications in the marine and industrial sectors. It also provides thermal and electrical insulation to protect parts from high temperatures and electrical currents. What’s more, there are non-stick and aesthetic finishes that ensure the finished product looks stylish in addition to being practical.