共沉淀法制备ZnO基纳米复合粉体及高压ZnO压敏电阻的电性能

以金属离子盐为原料,氨水、乙醇胺为沉淀剂,十二烷基苯磺酸钠、聚乙二醇2000为表面改性剂,采用共沉淀法制备ZnO基纳米复合粉体。以共沉淀法最佳工艺所得粉体制备高压ZnO压敏电阻。采用热重–差示扫描量热分析、X射线衍射、扫描电子显微镜、激光粒径分析对ZnO基复合前驱体及ZnO基纳米复合粉体进行表征,探讨了沉淀剂种类、溶液pH值、Zn2＋起始浓度和表面改性剂对粉体粒度的影响。结果表明：以氨水为沉淀剂、溶液体系pH值为6.0、Zn2＋浓度为1.0mol/L、聚乙二醇2000为表面改性剂时可制备出粒径分布窄、平均粒径为89nm的ZnO基复合粉体。用该粉体制备的高压ZnO压敏电阻的平均电位梯度为543V/mm,非线性系数为29.3,漏电流为49μA。通过共沉淀工艺,可制备出电性能优良的高压ZnO压敏电阻。

Preparation of ZnO-Based Nano-Composite Powder by Co-Precipitation and Electronic Properties of High-Voltage Zinc Oxide Varistor

ZnO-based nanoscale composite powders were prepared by a co-precipitation method using metal ion salts as raw materials, ammonia and ethanolamine as precipitants, sodium dodecyl benzene sulfonate and polyethylene glycol (PEG) 2000 as surfactants, respectively. The powders were characterized by thermogravimetry–differential scanning calorimetry, X-ray diffraction, scanning electron microscope and laser particle size analysis. The influencing factors such as precipitants, pH value, the initial Zn 2+ concentration and surfactants on the granularity of composite powder were discussed. The results show that the ZnO-based nano-composite powders with the average particle size of 89 nm and the narrower particle size distribution were synthesized using ammonia as a pre- cipitant and PEG 2000 as a surfactant at the pH value of 6.0 and the initial Zn 2+ concentration of 1.0 mol/L. A ZnO varistor prepared using the ZnO-based nano-composite powder mentioned had a mean potential gradient of 543 V/mm, a nonlinear coefficient of 29.3 and a leakage current of 49 μA. The use of the ZnO-based nano-composite powder for the ZnO varistor could provide an effective approach to prepare a high-voltage zinc oxide varistor with the superior properties.