All of these test methods are recommended for elementary quantification of the morphological properties of porous coatings bonded to solid substrates.

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

With the exception of using the alternate mounting method, all the methods should be performed on the same working surfaces. The alternate mounting method can only be used for 9.2 and 9.3.

A statistical estimate can be made of the distributions of the mean coating thickness and the volume percent void. No estimate can be made of the distribution of intercept lengths.

There are limits to the accurate characterization of porosity, depending on spacing between the lines in the line grid (or points in the point grid) and the individual and cumulative fields used for the measurements. Increasing the size of the fields, increasing the number of fields, or decreasing the grid spacing will increase the accuracy of the measurements obtained.

This method is not suitable for ceramic coatings for which accurate coating cross sections cannot be produced using metallographic techniques.

This test method does not address characterization of coatings having a thickness of less than 300 μm.