Metallographic preparation artifact in which carbide grains, ceramic splats or oxide fragments are ripped from the polished surface, leaving cavities that image analysis counts as pores. It is common in hard, brittle coatings prepared with coarse steps, too much force or worn cloths. Vacuum epoxy impregnation and careful diamond polishing reduce it, and inspectors learn to tell pullout from real porosity by edge shape.
That's pullout, not porosity, look at the sharp edges, repolish it with fresh diamond before you call it.
Also heard as
- pull-out
- grain pullout
Related terms
Mount
A polished cross section of a coated coupon set in resin, used to check structure under the microscope.
Porosity
The fraction of a coating's volume made of voids between and within splats, usually reported in percent.
Microhardness
Hardness of a coating measured with tiny diamond indents on a polished cross section.