Dielectric properties of barium titanate ceramics with different materials powder size

The dielectric properties of barium titanium ceramics fabricated with nano-size fine powders (about 40 nm) are compared with that fabricated with micro-size coarse powders (about 2 mu m). Three kinds of ceramics were fabricated; one using pure nano-size fine powders, the other using pure micro-size coarse powders, and the third using the combination of both. The sintering temperature of the ceramics with pure nano-size fine powders is 150 degrees C lower than that with pure micro-size coarse powders. For the same sintering conditions, the relative density of the ceramics is increases with the amount of nano-size fine powders. The grain size of the ceramics body with pure micro-size coarse powder is about 5 mu m, but that of pure nano-size fine powder is about 1 mu m. The room temperature dielectric constant of the ceramics increases with the increasing of the amount of nano-size fine powder. For pure nano-size fine powders, the room temperature dielectric constant is about 5000, and that of micro-size coarse powders is about 2200. (C) 2008 Elsevier Ltd and Techna Group S.r.l. All rights reserved.