Effect of CaCO₃ addition on the properties of CaZrO₃

Using analytical Ca(OH)₂ and m-ZrO₂ as the raw materials in the mole ratio of 1:1, the mixtures were added by CaCO₃ powders in the different contents by mass, the calcium zirconate (CaZrO₃) was synthesized by sintering the compacted samples at 1600 ℃ for 3 h. The effects of CaCO₃ powders on sintering properties, phase composition, and microstructures of CaZrO₃ were studied by apparent porosity density determinator, X-ray diffraction (XRD), scanning electron microscope (SEM), and X'Pert plus software. The results show that, without the addition of CaCO₃, the sharking of CaZrO₃ samples is 8.23%, the bulk density and apparent porosity of CaZrO₃ sintered at 1600℃ are 3.40 g·cm^-3 and 14.5%, respectively, and the grain size of CaZrO₃ is only 4.08 μm. With the addition of CaCO₃ in mass fraction of 8%, the sharking of CaZrO₃ samples is 14.89%, the bulk density and apparent porosity of CaZrO₃ sintered at 1600℃ are 4.02 g·cm^-3 and 8.6%, respectively, and the grain size of CaZrO₃ reaches to 5.45 μm. Thus, it can be seen that the CaCO₃ addition in appropriate content can promote the sintering compactness and grain growth of CaZrO₃.