The comprehensive study of the thermal etching conditions for partially and fully dense ceramic samples

Abstract

An alternative approach to the thermal etching of oxide ceramic materials (αalumina, t-zirconia, and c-zirconia) is presented and compared with the standardly used regime for thermal etching. The given approach was tested on partially (93.8 -96.3 % t.d.) and fully (99 -100 % t.d.) dense samples with the criterion of minimizing the density difference after and before etching and with the criterion of clear visibility of grain boundaries. The presented results show, that 900 °C/1 h etching regime is sufficient to reveal the studied microstructure for analysis of the surface of the samples sintered above 1355 °C without affecting the density and without thermal effect on the measured average grain size. The modern approaches as digital analysis of the images can help to reveal the thin grain boundaries after thermal etching at low temperatures.

SEraMic: A semi-automatic method for the segmentation of grain boundaries

“…Both methods require either the use of hazardous chemicals [2] or long heat treatments that often have to be optimised when working with new materials [3]. Finally, thermal etching could bias the measurements of grain sizes, particularly when grain growth, surface modifications [4,5,6,7], and/or secondary phase precipitation at the grain boundaries [8] occur during the heat treatment.…”