ZrO_2-10% Dy_2O_3纳米晶的碱性水热法合成及其烧结体的电性能研究

Hydrothermal Synthesis of ZrO_2-10% Dy_2O_3 Nanocrystallites in Basic Media and Electrical Properties of Their Sinters

以湿化学法制得Zr(OH)4和Dy(OH)3的共沉淀为前驱体, 在碱性介质(pH=7.60～13.89)中用水热法合成了ZrO2-10% Dy2O3(摩尔分数)立方相纳米晶. 研究发现, 纳米晶粒径随着反应介质pH值的增大而增大;同时纳米晶粒径随着水热反应介质温度的升高而增大. 将ZrO2-10% Dy2O3纳米晶在1400 ℃下烧结制得了致密的固体电解质陶瓷样品, 比通常高温固相反应法采用的烧结温度(＞1550 ℃)降低了150 ℃以上. 还用交流阻抗谱法及氧浓差电池法研究了ZrO2-10% Dy2O3陶瓷样品在600～1000 ℃下的离子导电特性. 结果表明, 该陶瓷样品在600～1000 ℃下氧离子迁移数为1, 氧离子电导率的最大值为2.2×10-2 S·cm-1, 是一个优良的氧离子导体.

ZrO2-10% Dy2O3 nanocrystallites with a cubic phase were prepared by hydrothermal method in basic media by co-precipitation of Zr(OH)4 and Dy(OH)3 from the solutions of ZrOCl2·8H2O and Dy2O3 dissolved in concentrated hydrochloric acid as precursors. It is found that the cubic nanocrystalline size is affected by pH value. The higher the pH value of reaction medium, the larger the nanocrystalline size. Green compacts made with the nanocrystallites prepared hydrothermally can be sintered to above 97% of theoretical density at 1400 ℃, which is 150 ℃ lower than that used by traditional high temperature solid state reaction. The results of XRD indicate that both the nanocrystallite and sinterd compact of ZrO2-10%Dy2O3 are of cubic phase. The oxide-ionic conduction properties of these sintered compacts were investigated by means of complex impedance and oxygen concentration cell at 600～1000℃. The maximal conductivity of the ceramics is 2.2×10 -2 S·cm -1 in dry O2 at 1000 ℃. The conduction in the ceramics are pure oxide-ionic with oxide-ionic transport number of 1 over the whole temperature range of 600～ 1000 ℃ .