Preparation Of Nano-sized ITO Powder And Dispersion Research

Indium tin oxide (ITO) is a tin-doped oxide semiconductor material. It is widely used as raw material of transparent conductive film because of high conductivity and excellent transparency. But most ITO films are manufactured by deposition and sputtering process, which limited its application considering its interest. In comparison with this, we wanted to prepare nano-sized ITO powders with dispersion performance which can be used directly in the manufacturing of transparent conductive and infrared shield coatings. As the product's cost decrease when using this particle , the extension of application is enlarged, which can be used in common materials.In this paper, conductive indium tin oxide( ITO) powders in size of nanometer were prepared by the hydrolysis of corresponding metal salts following co-precipitation technique using indium metal ingots and SnCl4 ·5H2O as raw materials. On the purpose of manufacturing functional powders in a large amount and energy-conserving, the factors in whole course were considered, especially the influences of co-precipitation terminal PH value and heat treatment temperature under hydrogen gas on the particle size and power resistance were discussed. The characteristics of powers were investigated by DTA-TG, XRD, TEM, Hall measurements, UV and conductivity meter.We also tried to prepare ITO nanometer powders with dispersion properties by adding some materials such as KC1 salt, NaCl salt and ethanol to indium tin metal salts in co-precipitation process. In which KC1 showed good effects.The results showed that functional nanometer ITO powders of 30-50nm size with dispersion performance can be prepared. The condition is that indium salt concentration is 88mmol/L, SnO2/In2O3 =5.3wt%, reaction solution PH value is 8, The precursor are thermally reduced at 450 ℃ under hydrogen gas ,at the sametime adding 6at.%( corresponding indium salt) KC1 salt to indium tin salts. Thus, satisfactory and stable dispersion of ITO particles in aqueous solution is obtained only through simple mechanical force. This dispersion solution can exist stably more than two months by adding dispersant. The product has high quality and the new process is simple with little contamination, low cost which has important applications in industry.