银掺杂对Bi_2O_3-ZnO-Nb_2O_5(BZN)系陶瓷熔融物性的影响

EFFECTS OF Ag DOPANT ON MELTING BEHAVIORS OF Bi_2O_3-ZnO-Nb_2O_5(BZN)-BASED CERAMICS

在BZN系陶瓷中 ,立方焦绿石结构的α相与低对称结构的β相是 2个重要的基本物相 .α相是熔点为 1190℃的同成分熔融化合物 ,β相是转熔温度为 110 0℃的异成分熔融化合物 .以差热分析(DTA)与X射线衍射 (XRD)分析为研究手段 ,明确了银掺杂对BZN系α相与β相熔融物性的影响 .结果表明 :银掺杂α相的熔点略有降低 ;银掺杂 β相的转熔温度下降到 10 0 0℃ ,银掺杂 β相在 10 0 0℃附近吸热分解为α相与液相 ,其转熔反应、淬冷析晶等现象 ,与无掺杂 β相相同 .

Cubic pyrochlore structure α phase and low symmetry structure β phase are the basic phases of BZN_based ceramics. The α phase is a congruent melting compound, its congruent melting point is 1 190 ℃. The β phase is an incongruent melting compound, its incongruent melting point (peritectic temperature)is 1 100 ℃. In this paper, the effects of Ag dopant on melting behaviors of BZN_based α phase and β phase have been explored via the DTA and XRD. The results show that Ag_doped α phase presents congruent melting behavior, its congru_ent melting point reduces a little. Ag_doped β phase shows incongruent melting behavior, dissociating to form α phase and liquid phase. Its incongruent melting point(peritectic temperature) is about 1 000 ℃. The peritectic reaction and phase separation on quenching show no significant difference from pure β phase.