Significance and Use
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.
Scope
1.1 This test method covers stereological test methods for characterizing the coating thickness, void content, and mean intercept length of various porous coatings adhering to nonporous substrates.
1.2 A method to measure void content and intercept length at distinct levels (“tissue interface gradients”) through the porous coating thickness is outlined in 9.4.
1.3 The alternate sample orientation method in 8.2 is not suitable for the tissue interface gradients method in 9.4.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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 and health practices and determine the applicability of regulatory limitations prior to use.
