The desmutting of etched or chemically polished aluminium surfaces is important to remove remaining tarnish and oxide layers before the anodisation process. This avoids possible staining or color changes of the anodised product. Often, the normal desmutting resources such as nitric acid, sulfuric acid or spent anodising bath solution are not sufficient to remove all impurities. This is where the addition of Alfideox 75 or Alfideox 79 can help.
Alfideox 75 is a stabilised, peroxide-containing additive that is used together with sulfuric acid or spent, aluminium-containing sulfuric acid for desmutting common aluminium alloys. The liquid product is highly effective even in low concentrations.
Alfideox 79 is a solid additive that is used to strengthen both nitric acid and sulfuric acid containing desmutting bathes. Particularly in combination with nitric acid, even poorly soluble alloy components can be removed.
Dark: desmutting bath with nitric acid only
Light: nitric acid + Alfideox 79
Advantages of Alfideox products 75 and 79
Alfideox 75 is already effective in low concentrations below 10 g/l
Alfideox 75 is stabilised, thus avoiding rapid decomposition
Alfideox 79 can be used in a wide range of concentration
Alfideox 79 is equally suitable for use in desmutting baths containing sulfuric acid or nitric acid
Alfideox 79 is particularly suitable for the removal of poorly soluble residues
Alfideox 75 and 79 can be analysed and thus precisely dosed