Microstructure, grain orientation, and properties of ITO ceramics sintered with various heating rates

Abstract

In this study, the microstructure, grain orientation, electrical resistivity, nanohardness, and fracture strength were systematically investigated in ITO ceramics sintered with different heating rates. It was found that ITO ceramics sintered at 1600°C consist of main phase (In 2 O 3 ) and secondary phase (In 2 SnO 5 ) and the distributions of coarse grains with high indium content and fine grains with high tin content are interval. The higher heating rate was found to refine the grain size and increase the {1000} textured secondary phase. The increase in electrical resistivity of ITO ceramics was due to the decrease in oxygen vacancies caused by the reducing oxide decomposition. Moreover, the nanohardness of fine grains was found to be higher than that of coarse grains due to the reinforcement effect of Sn element. Besides, the increase of heating rate is beneficial to enhance the fracture strength due to the higher resistance of grain boundary to fracture propagation and the predominantly intergranular fracture. K E Y W O R D Selectrical resistivity, fracture strength, grain orientation, In 2 SnO 5 , nanohardness