Techniques of Studying Microstructure

Individual grains in many fine ceramic materials are smaller in size than the section thickness, which leads to confusion, as the images in those cases will be superimposed ones. 

The polished sections are prepared by mounting the cut specimen in Bakelite or Lucite plastic and then grinding and polishing one face smooth, using a series of abrasive papers, followed by abrasive powders suspended in water on cloth wheels. 

The polished surfaces are observed directly with reflected light in a metallurgical microscope to distinguish the differences in relief or reflectivity between the different phases. The various phases are best distinguished after chemical etching, when the differences will be revealed 

This much thickness is obtained by chemical thinning or thinning by argon ion bombardment in addition to grinding. An advantage here is the selected area electron diffraction (SAD) patterns. This facility can be used to identify and characterize individual phases. 

Effect of porosity on direct electrical conductivity or on thermal conductivity upper curve, isolated spherical pores in a continuous solid matrix lower curve, isolated spherical particles in a continuous pore matrix. 

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