Sintering of tin-doped indium oxide (Indium-Tin-Oxide, ITO) with Bi2O3 additive

Tin-doped indium oxide (Indium-Tin-Oxide, ITO) is known as a poorly sinterable material. Densification of ITO powders with relatively large particle size (1-2 mu m) was enhanced remarkably by the additive (Bi2O3) whose melting point is lower than the sintering temperature. The maximum bulk density of 6.75 g/cm(3) (relative density; 95%) was obtained when pressurelessly sintered in air at 1500 degrees C for 5 hours using the starting material containing 2.0 mass % Bi2O3, while the density was approximately equal to the green density when sintered using the starting material without Bi2O3. Increase of electrical resistivity caused by the additive was suppressed successfully when a small amount of Bi2O3 (1.0 mass %) was added and heated at 1500 degrees C. The bismuth was eliminated from the sintered body to achieve the low resistivity (8.1 x 10(-4) ohm cm) which was approximately equal to that of the pure ITO. (C) 1998 Kluwer Academic Publishers.