Material-specific preparation of polished sections

After the individual grinding and polishing steps, the specimens must be thoroughly cleaned in an ultrasonic bath. This removes abrasive particles, polish particles, and swarf residue from the surface and pores of the specimen. These materials cannot be removed from the section surface by simple cleaning methods. 

The cleaned specimens should be examined by optical microscope after each preparation step, in order to monitor the quality of the section. This method makes it possible to quickly detect any defects resulting from processing and to optimize the sample preparation process with respect to time. 

The preparation process for ceramics can be modified by the introduction of materialographic lapping steps. Polishing times must be kept short in order to avoid the formation of relief. Diamond polishing produces a lower relief than polishing with substances of lesser hardness. 

Hygroscopic or water-soluble substances such as magnesium oxide, calcium oxide, and a-aluminum oxide must be prepared by the use of grinding and polishing fluids in a base of glycerol and oil and then cleaned in anhydrous liquids. 

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