Effects of precursor's grain size on syntheses and characteristics of CaZrO3 powders and (Ca,Ba)(Zr, Ti)O3 ceramics

Abstract

Effects of CaCO3 powder sizes on syntheses and characteristics of CaZrO3 powders and (Ba,Ca)(Ti,Zr)O3 (BCTZ) ceramics have been examined in a low-temperature co-firing technique. For the solid state reaction between CaCO3 and ZrO2 to synthesize CaZrO 3, the calcination temperature is decreased by applying ultra-fine CaCO3 powders. Moreover, the lowering of calcination temperature enabled to obtain highly dispersed CaZrO3 powders with fine grain (80 nm). For the solid state reaction between CaZrO3 and BaTiO 3 powder, the intermediate products depend on the initial grain size of CaZrO3 powders (80, 200 and 300 nm), indicating that reaction kinetics is obviously affected by the powder size of CaZrO3. The dielectric constants of BCTZ ceramics more markedly depend on the CaZrO 3 powder sizes and the reaction behavior between CaZrO3 and BaTiO3.