Specimen preparation method for the characterization in the transmission electron microscope of novel cermet powders used in thermal spraying processes

This paper describes a new method for the preparation of powder samples for their study in the transmission electron microscope. Novel TiC-WC-Ni and TiC-Ti-Ni powders—recently used in thermal spraying processes—were chosen. For the specimen preparation, the powder particles were embedded in a low-viscosity epoxy resin with the use of special molds and heated for 48 h at 60 °C. The embedded specimen was sliced with a diamond saw to about 500μm thick, and a 3mm diameter disc was obtained with a punch. This disc was ground to about 80μm thick, and a dimple was made in its center to achieve a final thickness of 30μm. Finally, the specimen was ion thinned by Ar+ ion beams. The samples obtained were electron transparent and could be studied by means of transmission electron microscopy. The new method allows the preparation of samples from hard powders used in thermal spraying processes that previously could not be examined in this way.