ISO 3210:2010 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 phosphoric acid/chromic acid solution.

ISO 3210:2010 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 phosphoric acid/chromic acid 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 phosphoric acid/chromic acid 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 architectural purposes. For less severe applications, Method 1 may 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 a treatment to render them hydrophobic.