Sintering study of ITO using a ZnO-doped and microwave hybrid sintering approach

ITO ceramics with full densities are difficult to achieve using conventional heating because of the volatilization property of both indium oxide (In2O3) and tin oxide (SnO2) at high temperatures. In our present study, we proposed to use a ZnO-doped and microwave hybrid-sintering approach to prepare for ITO ceramics with full densities under normal atmospheric condition. The investigation on the effect of the content of ZnO on the densification and resistivity of the ITO ceramics showed that as the ZnO content increased, the relative density of the ceramics increased while the weight loss and grain size decreased. The resistivity of the ceramics initially decreased by increasing the ZnO content but increased when the content of ZnO was more than 9.09 wt.%. Employing this logic, a relative density approaching 99% of the theoretical density was obtained and the sintering time required was just 25 min. The obtained ITO ceramics were pure ITO phase and had the lowest resistivity and the relative density of 98.1% when the content of ZnO was 9.09 wt.%. This hybrid sintering approach might open a new avenue in the fabrication of ITO ceramics with high densities.