5.1 All these test methods are recommended for elementary quantification of the morphological properties of porous coatings.

5.2 These test methods may be useful for comparative evaluations of different porous coatings or different lots of the same porous coating.

5.3 All the methods should be performed on the same set of images of fields.

5.4 Statistical estimates of the distributions of the mean coating thickness and the volume percent void can be made. No estimate can be made of the distribution of intercept lengths in any individual field because the intercept length of a field is a single value. It would be possible to make an estimate of the distribution from the single values from many different fields of the same coating system.

5.5 If the image resolution is sufficient, then increasing the size of the fields, increasing the number of fields, or decreasing the grid spacing will increase the accuracy of the measurements obtained.

5.6 This method may be suitable for ceramic coatings if an accurate coating cross section can be produced. Producing an accurate ceramic coating cross section may require techniques other than standard metallographic techniques.

5.7 For coatings created for roughness having a mean thickness less than 300 µm and a standard deviation to the mean thickness of greater than 15 %, the use of this standard to determine the volume percent void or mean void intercept length may have some limitations, which should be identified accordingly. (For example, if mean thickness is 250 µm and standard deviation is 100 µm, then the ratio of standard deviation to mean thickness is ~40 %, which is greater than the 15 % limit.)

1.1 This test method covers stereological test methods for characterizing the thickness, void content, and mean intercept length of various porous coatings either in bulk form or adhering to non-porous substrates.

1.2 A method to measure void content and intercept length at distinct levels (“Tissue Interface Gradients”) through the porous thickness is outlined in 9.4.

1.3 The values stated in SI units are to be regarded as the standard.

1.4 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.

1.5 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.