The standard outlines two main methods for evaluation, both requiring the use of a reflected light metallurgical microscope:
The primary goal of ASTM E2109-01 is to establish consistent procedures for "porosity ratings" on metallographic specimens. Because porosity—the presence of voids or "linear detachments" where coating layers haven't bonded—directly impacts a coating's corrosion resistance and structural integrity, having a standardized measurement is essential. astm e2109-01 pdf
: This method uses computerized image analyzers to calculate porosity more objectively, though it requires careful calibration to avoid "halo effects"—where the equipment incorrectly detects phase boundaries as pores. Critical Requirements for Accurate Testing The standard outlines two main methods for evaluation,
: It applies specifically to Thermal Sprayed Coatings (TSCs) . astm e2109-01 pdf
