Polishing is abrasion by free abrasives that are suspended in a lubricant and can roll or slide between the specimen and paper.  Polishing erases grinding marks and smooths the specimen to a mirror-like finish.  Polishing on a bare metallic platen is called lapping.  A typical polishing sequence for ceramics is 5&ndash;10 minutes each on 15-, 6- and 1-µm diamond paste or slurry on napless paper rotating at 240 rpm.  The specimen is again washed in an ultrasonic bath after each step.  The three sets of specimens in Fig. 3 have been sawed, embedded, ground and polished.