ASTM B681-88(1994) PDF

1.1 This test method covers a procedure for the nondestructive measurement of the thickness of transparent anodic coatings on aluminum articles by means of the light-section microscope. This method may also be used to measure the thickness of any transparent coating on an opaque reflective surface.

1.2 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.