4.1 Coating thickness is an important factor in the performance of a coating in service and is usually specified in a coating specification.

4.2 This method is suitable for acceptance testing.

1.1 This test method covers measurement of the local thickness of metal and oxide coatings by the microscopical examination of cross sections using an optical microscope.

1.2 Under good conditions, when using an optical microscope, the method is capable of giving an absolute measuring accuracy of 0.8 μm. Accuracy will determine the suitability of the method for measuring the thickness of thin coatings. Accuracy is dependent upon the setup of the microscope and preparation of the sample; 0.8 μm should not be taken as an absolute and instead as guideline.

1.2.1 Optical microscopes may use digital image capture devices and software to evaluate those images.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. (This is especially applicable to the chemicals cited in Table X2.1.)

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.