5. Characterization methods specific to ceramic powders

5.1 Morphology

The most direct technique for characterizing the morphology of a ceramic powder is electron microscopy. SEM is used for powders with grains no smaller than a micrometer, whereas in the case of powders made up of nanoparticles, TEM is used.

To prepare powder samples for SEM observation, a small cluster of grains is deposited on a conductive support (carbon "scotch tape") and metallized, if surface electron evacuation is not sufficient to avoid charging effects (this is generally the case for ceramics).

For TEM observation, the powder is suspended in a suitable solvent (water, ethanol, etc.) and dispersed using ultrasound. A drop of this suspension is then placed on a grid covered with an amorphous carbon membrane and air-dried....