Sulphuric acid anodising
This is probably the one you’ll hear about the most. Sulphuric acid anodising is popular because it just works. It is affordable, giving aluminium a nice protective finish. It is also great if you want to add colour since the coating holds dye really well.
This is usually the first option people go for.
Chromic acid anodising
This one is a bit more specialised. It is often used in aerospace, where even tiny changes in size can be a problem.
It is not as decorative, but it does the job when accuracy matters. If you want to compare it with other methods like sulphuric acid anodising, this guide is worth a look www.poeton.co.uk/surface-treatments/anodising/sulphuric-acid-anodising/.
Hard anodising
This is the tough option. Hard anodising gives you a much thicker and stronger coating, so it is perfect for parts that deal with a lot of friction or wear.
It is commonly used in engineering where things need to last and keep performing over time. According to this BBC look at advanced materials in engineering, surface treatments like this play a big role in making components more durable.
Phosphoric acid anodising
This one is more of a prep step than a finish. It helps surfaces bond better with paint or adhesives. That is why it is often used in industries like automotive and aerospace where strong joins are essential.
Boric acid anodising
Not as common, but still useful. Boric acid anodising is often chosen as a more environmentally friendly option. It gives decent protection without relying on some of the harsher chemicals used elsewhere.
