| abstract |
The present invention describes a method for the post-treatment of fully sealed anodised aluminum parts, especially for the automotive industry, characterised in that an aqueous silicate solution is applied to fully sealed anodised aluminum layers, where said fully sealed anodised aluminum layer has a film thickness of at least 5 µm and a film weight of at least 13 g/m 2 , respectively. Said solution preferably contains an alkaline metal (M) silicate with not more than 2.0 wt.-% of SiO 2 , in which the ratio of SiO 2 : M 2 O is preferably not more than 2. This treatment increases the alkaline stability according to the standardised corrosion tests in the automotive industry without any further treatment or organic coating applied to said treated aluminum surface. |