采用固相法制备了Ca Cu3Ti4O12多晶块体,研究了其介电常数随温度和频率的变化。结果表明,在温度为300 K、频率为1 k Hz时,多晶块的介电常数高达14 000;频率为1 k Hz时,介电常数基本不随温度的变化而改变。动态变化的极化弛豫使Ca Cu3Ti4...采用固相法制备了Ca Cu3Ti4O12多晶块体,研究了其介电常数随温度和频率的变化。结果表明,在温度为300 K、频率为1 k Hz时,多晶块的介电常数高达14 000;频率为1 k Hz时,介电常数基本不随温度的变化而改变。动态变化的极化弛豫使Ca Cu3Ti4O12多晶块具有巨介电常数,混合价Ti离子导致极化子的热激活使Ca Cu3Ti4O12多晶块的介电特性出现反常效应。展开更多
Bismuth titanate （Bi4Ti3O12） platelets were prepared by molten salt method in a new salt system of CaCl2·NaCl at 650-750℃, using bismuth nitrate pentahydrate （Bi （NO3）3·H2O） and titanium butoxide （Ti...Bismuth titanate （Bi4Ti3O12） platelets were prepared by molten salt method in a new salt system of CaCl2·NaCl at 650-750℃, using bismuth nitrate pentahydrate （Bi （NO3）3·H2O） and titanium butoxide （Ti （OC4H9）4） as raw materials. The synthesis temperature of Bi4Ti3O12 platelets was decreased to 650℃ from 900-1100℃. The phase compositions and crystalline morphology of Bi4Ti3O12 platelets were investigated by XRD and SEM. The experimental results indicate that Bi4Ti3O12 platelets containing tetragonal and orthorhombic phase with the size of 1-3μm can be synthesized at 650℃ for 2 h, and the orthorhombic phase becomes the dominant phase at 750℃ for 5 h. The size and proportion of Bi4Ti3O12 platelets increase with the increment of the calcining temperature and holding time. The proportion of platelets increases to about ninety percent, and the platelets grow up to about 3-10μm at 750℃ for 5 h from 1-2μm at 650℃ for 2 h. This technical route provides a new low-temperature molten salt system for preparing platelets by molten salt methods.展开更多
文摘采用固相法制备了Ca Cu3Ti4O12多晶块体,研究了其介电常数随温度和频率的变化。结果表明,在温度为300 K、频率为1 k Hz时,多晶块的介电常数高达14 000;频率为1 k Hz时,介电常数基本不随温度的变化而改变。动态变化的极化弛豫使Ca Cu3Ti4O12多晶块具有巨介电常数,混合价Ti离子导致极化子的热激活使Ca Cu3Ti4O12多晶块的介电特性出现反常效应。
文摘Bismuth titanate （Bi4Ti3O12） platelets were prepared by molten salt method in a new salt system of CaCl2·NaCl at 650-750℃, using bismuth nitrate pentahydrate （Bi （NO3）3·H2O） and titanium butoxide （Ti （OC4H9）4） as raw materials. The synthesis temperature of Bi4Ti3O12 platelets was decreased to 650℃ from 900-1100℃. The phase compositions and crystalline morphology of Bi4Ti3O12 platelets were investigated by XRD and SEM. The experimental results indicate that Bi4Ti3O12 platelets containing tetragonal and orthorhombic phase with the size of 1-3μm can be synthesized at 650℃ for 2 h, and the orthorhombic phase becomes the dominant phase at 750℃ for 5 h. The size and proportion of Bi4Ti3O12 platelets increase with the increment of the calcining temperature and holding time. The proportion of platelets increases to about ninety percent, and the platelets grow up to about 3-10μm at 750℃ for 5 h from 1-2μm at 650℃ for 2 h. This technical route provides a new low-temperature molten salt system for preparing platelets by molten salt methods.
