中文摘要：

以Bi（NO）3·5H2O和Fe（NO）3·9H2O为水热反应原料,选择KOH作为矿化剂合成单相BiFeO3.通过调节KOH浓度和升降温速率可控合成了规则的大尺度多面体BiFeO3颗粒.发现高碱浓度有利于合成规则多面体BiFeO3颗粒,合适的水热降温速率是影响高结晶度BiFeO3颗粒合成的重要因素之一.当KOH浓度为6和8 mol/L,降温速率为0.2℃/min时,产物为高结晶度准立方和截角立方颗粒,当降温速率调节为0.1℃/min时,产物为表面粗糙的立方八面体和截角八面体颗粒.当KOH浓度为8 mol/L,降温速率约为2℃/min时,产物为表面粗糙且有孔洞的截角立方颗粒.通过扫描电镜图片观察到其形貌演变过程并解释了大尺度多面体BiFeO3颗粒的形成机制.

英文摘要：

Bismuth ferrite（BiFeO3） powders were hydrothermally synthesized by using Bi（NO）3？5H2O and Fe（NO）3？9H2O as starting materials,and KOH used as a mineralizer.The large-scale polyhedral BiFeO3 particles were obtained by controlling KOH concentration,heating and cooling rate.It was found that the large-scale polyhedral BiFeO3 particles were synthesized favorably at the high KOH concentrations and an appropriate cooling rate was an important factor for synthesis of high crystallinity BiFeO3 particles.The quasi-cubic and truncated cubic particles of high crystallinity were obtained at the KOH concentration of 6 and 8 mol/L with the cooling rate of 0.2℃/min,respectively.The rough cubo-octahedron,truncated octahedron particles were obtained by changing the cooling rate to 0.1℃/min.The rough truncated cubic particles with pores were obtained by changing the cooling rate to 2℃/min.Morphologies evo-lution of large-scale poledron bismuth ferrite particles were observed by scanning electron microscope.The forma-tion mechanism of the regular morphologies was also discussed.