Study Of Doped Indium Tin Oxide (ITO)Microwave Sintering

ITO (Tin-doped indium oxide) targets, as an important material that can be used for the fabrication of transparent conductive films, have been widely used in many fields. However, ITO targets with full densities are difficult to achieve using conventional sintering in the air atmosphere because of the volatilization property of both indium oxide (In2O3) and tin oxide (SnO2) at high temperatures.Recently, microwave sintering has received much attention, because of its desirable advantages, such as reduced activation energies, lower sintering temperatures, enhanced diffusion processes, very rapid heating rates and so on. However, it is still difficult to achieve full density of ITO only by using pure microwave heating under a low level of microwave power. In our present study, we proposed to use a dopant doped and microwave hybrid sintering approach to prepare for ITO targets with full densities under normal atmospheric condition. This hybrid approach combines the advantages of doping and microwave sintering. In our study, ZnO, Sb2O3and Ti3N4were choosed as the dopant and the effect of the amount of dopant on the densification, resistivity and microstructure of the ceramics would be investigated so as to obtain high-density ITO ceramics with a low resistivity.The results from the investigation on the effect of the content of ZnO on the densification and resistivity of the ITO targets showed that as the ZnO content increased, the relative density of the targets increased while the weight loss and grain size decreased. The resistivity of the targets initially decreased with increasing the ZnO content but increased when the content of ZnO was more than9.09wt%. Using this method, a relative density approaching99%of the theoretical density was obtained and the sintering time required was just25min. The obtained ITO targets were pure ITO phase and had the lowest resistivity and the relative density of98.1%when the content of ZnO was9.09wt%.The effect of the Sb2O3content on the microstructure, densification and electrical properties of ITO ceramics were investigated. The results showed that the relative density reached98.3%by using the hybrid sintering approach. The resistivity of the obtained targets showed a decrease tendency with increasing the Sb2O3content in the range of0to 1.5wt%.The results from the investigation on the effect of the Ti3N4content on the microstructure, densification and electrical properties of ITO ceramics showed that the relative density reached98.2%by using the hybrid sintering approach. The resistivity of the obtained targets showed a decrease tendency with increasing the Sb2O3content in the range of0to0.5wt%.This hybrid sintering approach might provide a new route for the fabrication of ITO ceramics with high densities.