摘要
采用Sol-gel法合成了BaTiO3、BaTi2O5和BaTi4O9粉末,利用XRD和SEM研究了它们的晶相和微观结构。在较低温度烧结得到的粉末都存在一定量的杂相,随着烧结温度的升高,杂相逐渐消失。在1000℃以上温度烧结,可以得到单相BaTiO3和BaTi2O5粉末,而单相BaTi4O9粉末则在1300℃以上温度烧结得到。随着n(Ba)/n(Ti)减小,所得单相的烧结温度逐渐升高。随着烧结温度的升高,BaTiO3、BaTi2O5和BaTi4O9粉末的晶粒逐渐长大。800℃以上温度烧结得到的四方BaTiO3钙钛矿相粉末主要由方形和圆形的晶粒组成;1100℃烧结得到的单斜BaTi2O5相粉末主要由近似菱形的晶粒组成;在1200℃烧结得到的正交BaTi4O9相粉末基本由长形的晶粒组成。
BaTiO3, BaTi2O5 and BaTi4 O9 powders were prepared by a sol-gell method. The crystallization and microstructure were investigated by XRD and SEM, respectively. There were small amount of second phases in the powders sintered at low temperature. With increasing temperature, the amount of second phases decreased. The sin gle-phase BaTiO3 and BaTi2O5 powders were obtained above 1000℃, while the single-phase BaTi4O9 powders were sintered above 1300℃. With decreasing Ba/Ti molar ratio, the sintering temperature to obtain the single phase in- creased. The grains of BaTiOa, BaTi2O5 and BaTi4 O9 powders became larger as the sintering temperature increased. The tetragonal BaTiOa powders sintered above 800℃ mainly consisted of square and round grains. The monoclinic BaTi2O5 powder,s sintered above 1100℃ mainly composed of rhombic grains. There were mainly oblong grains existed in BaTi4O9 powders sintered above 1200℃.
基金
中国科学技术部国际科技合作项目(2009DFB50470)
教育部新世纪优秀人才支持计划(NCET-10-0662)
国家自然科学基金青年科学基金(50902108)
