Abstract:
Sr
2Nb
2O
7 powder was prepared by solid-state reaction method, and then Sr
2Nb
2O
7 ceramics were prepared by two-step textured sintering process. The microstructure, phase composition and the change of resistivity with temperature and time of the ceramics were studied. The results show that the ceramics had a pure phase. The structure was composed of plate-like grains and the grains were oriented well along the pressing direction. The high temperature resistivity of the ceramics decreased with the increase of temperature. During holding at 800℃ for 125 h, the resistance of the perpendicular samples (normal direction of the sample surface was perpendicular to the pressing direction) did not deteriorate. At 980℃ and 1 000℃, the perpendicular samples showed resistance degradation behavior, and the breakdown occurred after holding for 20 h and 1 h, respectively. At 1 000℃, the parallel sample (normal direction of the sample surface was parallel to the pressing direction) had relatively long degradation time of resistivity because of the relatively large number of grain boundaries.