Bi_2O_3-ZnO-Nb_2O_5三元系统中焦绿石结构及相变

PYROCHLORE STRUCTURE AND PHASE TRANSITION OF THE Bi_2O_3-ZnO-Nb_2O_5 SYSTEM

文章研究了 Ｂｉ２Ｏ３－ＺｎＯ－Ｎｂ２Ｏ５（ＢＺＮ）三元系统中的焦绿石结构与相变．用 Ｘ－射线衍射（ＸＲＤ）技术分析研究了样品（Ｂｉ３ｘＺｎ２～３ｘ）（ＺｎｘＮｂ２～ｘ）Ｏ７（０．４≤Ｘ≤０．６７）的相结构及相组成，发现了两种焦绿石晶相（立方α相和单斜β相）及其复相（α＋β）结构．且随着ｘ值的增加，晶体结构从焦绿石立方相向焦绿石单斜相逐渐过渡；焙烧温度的升高和保温时间的延长有利于焦绿石立方相的形成．

The pyrochlore structure and phase transition of the Bi203-ZnO-Nb203 system were in-vestigated. Samples of compositions (Bi3xZn2-3x)(ZnxNb2-x)O7(0. 4≤X≤0. 67) were pre-pared, the phase structure and phase formation were analyzed by X-ray diffraction (XRD) technology. The crystal phases were characterized as cubic pyrochlore (α), monoclinic py-rochlore(β), as well as the α-β coexisting phases. The crystal structure gradually transforms from phase α to phase β as the value of X increases. Higher sintering temperature and longer incubation time are beneficial to the formation of α phase.