As a further surface refinement for aluminium, we offer you anodising.
The anodising process stands for the electrolytic oxidation of aluminium and is a process for the surface treatment of aluminium. During anodising, anodic oxidation is used to create an oxidic protective layer on the metal. In contrast to galvanising, no protective layer is applied here, but an oxide layer is formed by the transformation of the metal surface. This layer is firmly bonded to the aluminium, as it is formed from the metal itself.
The oxide layer formed by the aluminium itself is very thin at a few nm. Anodizing creates a layer with a thickness of 5-25 µm, which ensures better corrosion protection.
Anodizing is also called passivation, because the corrosion of the metal is slowed down or completely prevented.
With this process, aluminum can be colored in the desired color and protected by a hard, wear-resistant layer.
Electrogalvanizing provides corrosion protection, but can also be used to improve the appearance of components (decorative galvanizing).
In contrast to hot-dip galvanizing, the sheet is not immersed in a molten zinc bath but in a zinc electrolyte. In this case, the workpiece is the cathode, the anode is an electrode made of the purest possible zinc.
Due to the significantly lower layer thickness of only 3µm to 20µm, electrogalvanizing is not an option as protection for parts in outdoor use (outdoor weathering).
However, there are advantages when galvanizing sheets with finer perforations. The holes do not clog. Another advantage is that the sheets or grids do not warp due to the low temperature of the electrolyte of 20°C to 60°C!
Pickling of stainless steel is used for corrosion resistance of non-rusting steels, because even stainless steel in untreated form can rust after welding or mechanical processing.
Pickling is a surface treatment with the aid of chemicals, such as acid or lye. The aim of the process is to change the outer layer of the material and thus improve its corrosion resistance.
Pickling is always necessary when the optimum surface condition for corrosion resistance is no longer ensured, e.g. due to: Formation of tarnish due to welding or grinding, residues of weld spatter or also deposits of metal oxides.
After the previous pickling process, the stainless steel parts are provided with a passivation layer. This layer serves as corrosion protection for the stainless steel.