【作者】 吴其昌； 王慧萍； 田琼； 廖恒成；

【Author】 WU Qi-chang WANG Hui-ping TIAN Qiong LIAO Heng-cheng (School of Material Science and Engineering,Southeast University,Nanjing 211189,China)

【机构】 东南大学材料科学与工程学院；

【摘要】 采用溶胶-凝胶法在醋酸溶液体系申制备了未掺杂和掺 Mg 的钛酸锶钡的凝胶和粉末．通过 DSC-TG 考察了 Mg 掺杂对 BST 凝胶热解与晶化过程的影响,XRD 分析了 Mg 掺杂的 BST 粉末的相组成．结果表明：Mg 掺杂强烈影响 BST 体系的热演变过程,特别是晶化过程, 由未掺杂的双相变过程变成单相变过程．随着 Mg 掺杂量增加,BST 相晶化开始温度下降（提前）,低于10% 的 Mg 掺杂使晶化反应速度加快．在相同热经历状况下, Mg 掺杂 BST 体系晶化反应充分完全,BST 相结晶性良好．随 Mg 掺入量增多,BST 体系中（Ba,Sr）CO₃相的量增多,Mg 进入晶格是（Ba,Sr）位替代而非 Ti 位替代． BST 晶体（110）晶面间距 d 随 Mg 的掺入增大；BST 粉的晶粒大小随 Mg 的掺入逐渐减小,当 Mg 掺杂量分数为10% 时晶粒最细小．更多还原

【Abstract】 Gels and powders of Ba_0.7Sr_0.3(Ti_1-xMg_x)O₃ were prepared by sol-gel technique.Influence of Mg-doping on the pyrolysis evolution of BST was analyzed using DSC-TG,and the Mg-doped BST powders were analyzed by XRD.Results show that the Mg-doping leads to a remarkable change of the crystallizing process of BST from a double phase-transformation of non-doping sample into a single phase-transformation.With increase in the level of Mg dopant, the onset temperature of the crystallizing reaction decreases,and the reaction rate of crystallizing of BST increases considerably with the level of Mg dopant within 0.10.The crystallizing of the Mg-doped BST powders is more complete and the crystallinity of BST phase of them is better than that of the non-doped sample.The amount of （Ba,Sr）CO₃ phase in the BST powders increases considerably with the level of Mg dopant,and hence,it is rational to think that Mg atoms entering into the lattice of ABO₃ structure of BST substitute A position,instead of B position.With increase in the level of Mg dopant the plane spacing of （110） of BST crystals increases and the grain size of the BST powders decreases.The BST powder with Mg dopant concentration of 0.10 has the smallest grain size.更多还原