【作者】 刘俊生；

【导师】 刘胜峰；

【作者基本信息】 合肥工业大学 ， 化学工艺， 2004， 硕士

【摘要】 研究了溶胶-凝胶法制备Ca²⁺、Mn²⁺共掺杂Ba_xSr_1-xTiO₃合成Ba_0.4Sr_0.5Ca_0.08Mn_0.02TiO₃固溶体的动力学参数，结果表明：热处理温度升高，微晶结构从无序向有序转变，同时晶粒呈规则的四边形态。提高升温速率，晶化峰顶温度升高，晶化放热峰向高温方向移动。由立方相向四方相转变的煅烧温度约700～850℃，晶化表观活化能为152.04kJ／mol。只有使用冰醋酸溶解钡、锶氢氧化物才能制得Ba_0.4Sr_0.5Ca_0.08Mn_0.02TiO₃完全固溶体，螯合剂加入量的最大摩尔比为1.0。R-V和R-T曲线显示：不掺杂的BST标准样品在1kHz时阻抗值随外加直流偏压的增大，先减小然后逐渐增大，当直流偏压为25v时，不在增加。掺Ca的BST样品在1kHz时阻抗值逐步减小，在外偏压20v时有一个跳跃式的下降，然后再缓慢降低；并且掺Ca有利于降低BST的电阻。掺Mn可降低BST的电阻值，但又随外偏压增大而增大。低频1kHz时，阻抗值随温度的增加而升高；并且阻温特性曲线出现异常双峰效应，并且双峰随频率增大向低温移动。更多还原

【Abstract】 The effect of different concentration of acetic acid on calcium and manganese doping BaxSr1-xTiO3 ,and kinetic parameters of Ca and Mn Codoping BaxSr1-xTiO3 to prepare Ba0.4Sr0.5Ca0.05Mn0.02TiO3 solid solution were studied. The Results indicate that using 36%HAc, Bao.4Sr0.5Ca0.1-xMnxTiO3 solid solution can be prepared and there is no change of crystallization phase; but when glacial acetate acid is used, the crystallization phase changes and the temperature of crystallization phase is about 700℃. When the concentration of acetic acid is increased, the crystallization temperature decrease, at the same time, the structure of microcrystals is transformed from disorder into order and crystallite become regular tetragonal system. In addition ,the structure of microcrystals is transformed from disorder into order as heating temperature increases, and crystallites become regular tetragonal system . The crystallization temperature increases when heating rate is risen and apparent activation energy of crystallization is 152.04 kJ/mol.Only using glacial acetate acid to dissolve barium and strontium hydroxide,the sol-gel of Ba0.4Sr0.5Ca0.08Mn0.02TiO3 can be derived, and the maximum mole ratio of chelating agent content on the sol-gel is about 1.0. Complex impedance-measurements were used to separate the resistance of grain Rb, and grain boundaries as Rgb. The experiment shows that manganese can not affect the perovskite phase,but can influence the resistance-voltage characteristics in low frequency,the resistance value was lowed from 10381k to 1076k , about 10 times.更多还原