锑掺杂氧化锡包覆氧化钛浅色导电粉的过程与模型

为了掌握沉淀反应包覆掺锑氧化锡膜形态和工艺参数对导电粉电阻率的影响规律,本文中详细研究了采用沉淀法在氧化钛表面包覆掺锑氧化锡的过程。通过采用透射电镜观察包覆产物结构,并对不同pH值下的包覆产物进行了光电子能谱分析。结合氧化钛和氧化锡水溶液的Zeta电位,提出了包覆过程和模型。结果表明:包覆过程是先均相形核,然后锡溶胶靠静电引力与范德华力共同作用吸附在氧化钛表面;当沉淀pH=2时,氧化锡以直径为5nm胶粒单层密排在氧化钛表面,此时导电粉具有最佳导电性。

Mechanism of Forming Sn(Sb)O2Coating on TiO2 Powder in a Co-precipitation Process

The white conductive powder was prepared by co-precipitation method, using SnCl4·5H2O, SbCl3 and ultra-fine TiO2 powder as precursors. XPS and TEM were applied to characterize the contents and structure of the materials obtained under different pH condition. The mechanism of forming antimoy tin oxide(ATO) coating on TiO2 was systematically investigated. The mechanism of formation of coating was suggested as xSn(Sb)O2·yH2O were formed as colloidal particles,then adsorbed on TiO2 surface by Van de Waals force and electric force. When co-precipitated under pH=2, single layer of ATO particles of 5 nm in diameter were arrayed on surface of TiO2. The conductive powders obtained under pH=2 has best conductivity.