scope:

NEN-EN-ISO 3210 specifies methods of assessing the quality of sealed anodic oxidation coatings on aluminium and its alloys by measurement of the loss of mass after immersion in acid solution(s). It consists of the following two methods. - Method 1: Assessment of quality of sealed anodic oxidation coatings by measurement of the loss of mass after immersion in a phosphoric acid based solution without prior acid treatment. - Method 2: Assessment of quality of sealed anodic oxidation coatings by measurement of the loss of mass after immersion in a phosphoric acid based solution with prior acid treatment. Method 1 is applicable to anodic oxidation coatings intended for decorative or protective purposes or where resistance to staining is important. Method 2 is applicable to anodic oxidation coatings intended for outdoor architectural purposes. For less severe applications, Method 1 can be more suitable. The methods are not applicable to the following: - hard-type anodic oxidation coatings which normally are not sealed; - anodic oxidation coatings that have been sealed only in dichromate solutions; - anodic oxidation coatings produced in chromic acid solutions; - anodic oxidation coatings that have undergone treatment to render them hydrophobic.