| Summary: | Thermal etching is a widely accepted surface treatment method for studying microstructure in Na<sub>0.5</sub>Bi<sub>0.5</sub>TiO<sub>3</sub>-based compositions. Surprisingly, besides the flat pattern of grains (suitable for evaluating ceramics’ microstructure), images illustrating well-expressed relief and even microstructure consisting of partly bonded cubic-shaped grains are also found among the micrographs presented in various publications. The present paper shows that this different surface character in Eu-modified Na<sub>0.5</sub>Bi<sub>0.5</sub>TiO<sub>3</sub> can be obtained through thermal treatment across a wide range of temperatures. At higher temperatures, remarkable growth of cubic-shaped grains on the surface is observed. This growth affects the grain size distribution on the surface more than it does within the bulk of a sample. Such micrographs cannot be used to characterise the microstructure of dense ceramics. Intensive growth of TiO<sub>2</sub> inclusions at high thermal treatment temperatures is also observed, revealing substantial evaporation of Bi and Na from the surface of a ceramic sample, but not from its core part.
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