pickling treatment without any visually perceptible difference between their surfaces profile sections of extruded aluminium profiles of the alloy almgsio 5 were removed from a pressing plant for comparative tests sieve fractions of sieve sizes d 90 of from 0 1 mm to 0 2 mm mesh size of both angular material and spherical material were produced from blasting materials of a german manufacturer the round blasting material was stainless steel having a chromium content of 18 by weight u00b1 1 by weight and a nickel content of 10 by weight u00b1 2 by weight the angular blasting material was stainless steel having a chromium content of 30 by weight u00b1 1 by weight and a carbon content of 2 by weight u00b1 0 1 the prepared profile sections were then blasted in a manual cabinet with variable compressed air pressure mixtures of the spherical and angular sieve fractions also being used after blasting the profile sections were first cleaned in a cleaner for aluminium surfaces from alufinish product alficlean then pickled gently for one minute in a dilute sodium hydroxide solution 50 g l at 60 u00b0 c and then deoxidized in an acidic solution of 150 g l of sulfuric acid and a peroxidic additive alfideox from alufinish 1 g l and then anodized in a bath containing 180 g l of sulfuric acid a current density of 1 5 a dm was used the anodization time was 40 minutes until a layer thickness of 20 u03bcm was.