ASTM B748

ASTM B748 – Standard Test Method for Measurement of Thickness of Metallic Coatings by Measurement of Cross Section with a Scanning Electron Microscope

Description:

Significance and Use

4.1 This test method is useful for the direct measurement of the thicknesses of metallic coatings and of individual layers of composite coatings, particularly for layers thinner than normally measured with the light microscope.

4.2 This test method is suitable for acceptance testing.

4.3 This test method is for the measurement of the thickness of the coating over a very small area and not of the average or minimum thickness per se.

4.4 Accurate measurements by this test method generally require very careful sample preparation, especially at the greater magnifications.

4.5 The coating thickness is an important factor in the performance of a coating in service.

Scope

1.1 This test method covers the measurement of metallic coating thicknesses by examination of a cross section with a scanning electron microscope (SEM).

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.