Sintering of Additive Free Hydrothermally Derived Indium Tin Oxide Powders in Air

High-density and chemically homogeneous Sn-doped (0-10 mole%) indium oxide (ITO) ceramics have been successfully prepared using a highly sinterable hydrothermally derived InSn oxyhydroxide fine powder as the starting material. Low-temperature calcination at 500°C of the hydrothermally prepared phase led to formation of a substitutional vacancy type solid solution of In2Sn1-xO5-y. The sintering behavior of the calcined powder compacts was studied at temperatures from 1200 to 1500°C for 3 h in air. C-type rare-earth oxide structured ITO ceramics were obtained with fine microstructures and fewer pores. Neither the O2 sintering atmosphere nor sintering aids were used to promote the densification of ITO ceramics. It was found that the addition of Sn to In2O3 propelled the densification.