Transmission electron microscopy characterization of spark plasma sintered ZrB2 ceramic

Microstructures of ZrB2 ceramics consolidated by hot-pressing and spark plasma sintering were investigated by transmission electron microscopy (TEM), combining energy dispersive X-ray spectroscopy (EDX). The microstructures of both ceramics were compared. Amount of impurities was lower for ZrB2 consolidated by spark plasma sintering than for hot-pressed ZrB2. In particular, oxygen impurity was not detected even at the grain-boundaries in ZrB2 consolidated by spark plasma sintering. The cleaning effect generated on the powder surfaces during spark plasma sintering cycle was displayed. In addition, dislocations were present only in the spark plasma sintered ZrB2 ceramic, as a result of localized high stresses.