Characterization of liquid phase in (Na_0:5K_0:5) NbO₃ ceramics with V₂O₅ additions

The characterizations of the microstructure and the chemical compositions on (Na_0:5K_0:5)(Nb_0:93V_0:07)O ₃ ceramics system sintered at 900 °C for 8 h were carried out using high resolution transmission electron microscopy (HRTEM), energy filtered (EF) TEM, and energy dispersive spectroscopy (EDS). The liquid phase was found at the triple junction of the grains and abnormal grain growth occurred in the presence of liquid phase. The liquid phase has formed by the melting of V ₂O₅ at the sintering temperature. The presence of V element in liquid phase was confirmed by EDS analyses. The interface between the matrix phase and the liquid phase was atomically flat and consists of a stepped ledge structure of one or two atomic height. The KVO₃ phase which may be formed during the cooling of the specimens was observed at these interfaces and have a good orientation relation with the matrix.