Effects of liquid phase formation on the order-disorder behavior of Ba(Ni1/3Nb2/3)O3

Abstract

The order-disorder behavior of Ba(Ni1/3Nb2/3O3 has been investigated using various heat treatments. Heat treated samples were characterized using X-ray diffraction, transmission electron microscopy, and energy-dispersive spectroscopy, interactively. It has been confirmed that the formation of Nb-rich liquid phase resulted in an increase in defect concentration of matrix grains and favored disordering. Ba(Ni1/3Nb2/3O3, however, showed a drastical change in order-disorder behavior by the heat treatment history. The samples prepared from the calcined powder showed a transition from disorder to order with increasing sintering time at 1400°C whereas the samples preheat treated at 1300°C for 100 h showed a transition from order to disorder at 1500°C. This difference in order-disorder behavior has been discussed in terms of the order-disorder phase boundary, liquid-phase sintering, and the nucleation and growth. The growth process of ordered precipitates was also suggested. ？ 1995, Taylor & Francis Group, LLC. All rights reserved.