DIN EN ISO 2143:2010-12

Anodizing of aluminium and its alloys- Estimation of loss of absorptive power of anodic oxidation coatings after sealing- Dye-spot tests with prior acid treatment (ISO/FDIS 2143:2010) This standard specifies a method of estimating the loss of absorptive power of anodic oxidation coatings by dye-spot test with prior acid pre-treatment. The method is suitable for use as a production control method and is applicable to anodic oxidation coatings which are subjected to weathering or aggressive environmental influences, or where resistance to staining is important. The method is not applicable to those coatings that - are formed on alloys containing more that 2 % copper or 4 % silicon - are sealed in dichromate solutions - have been given supplementary processing, for example, oiling, waxing or lacquering - are coloured in deep shades - are less than 3 µm thick. The method is less appropriate where nickel or cobalt salts, or organic additives, have been added to the sealing bath. In principle the following shall occur: A degreased area of sample is treated with acid. After the application of a dyestuff the coloration of the surface is evaluated. Note: The German version, as well as in the previous national standards, are concerned with the estimation of the loss of absorptive power, whereas in the English and French versions the estimation of absorbency is discussed. That means, that in Annex A "No loss of absorptive power" and "Total loss of absorptive power" have the same status. The International Standard has been prepared under the leadership of ISO/TC 79/SC 2/WG 16 "Revisions for systematic reviewed TC 79/SC 2 ISO standards" (secretariat: JISC, Japan) in a parallel procedure with CEN/TC 132/WG 15 "Aluminium anodisation" (secretariat: BSI, United Kingdom). On the national level the responsible Working Committee is NA 066-01-09 AA "Anodisch oxidiertes Aluminium" ("Aluminium anodisation") of FNNE.