Characterization of CaO-ZrO2 and CaO-ZrO2-Al2O3

Abstract

This study is focused on production of partially stabilized zirconia containing 8mol% CaO and examination of effect of Al2O3 adding on it. Zirconia nanopowders were synthesized by the precipitation method from zirconium sulfate precursors. Precipitateswere dried at 80 ◦C for 72 h, and CaCO3 powderswere added to dried powders. Then this powder mixture was calcinated at 1300 ◦C for 1 h. And the second powder mixturewas prepared by adding wt.%10 Al2O3 to calcinated powders. Each powder mixture were pressed under uniaxial compression of 300 MPa and sintered at 1600 ◦C for 1 and 2 h in an open atmospheric electrical resistance furnace. Relative densities of sintered samples measured in terms of Archimedes’ principle were about 99% for CaO-ZrO2 and 97.5% for CaO-ZrO2-Al2O3. XRD analysis revealed that sintered CaO-ZrO2 has monoclinic, tetragonal or/and cubic zirconia and sintered CaO-ZrO2-Al2O3 has similar phases to CaO-ZrO2 has, differently include CaAl12O19 phase. SEM-EDS analyses showed that the sintered samples have inhomogeneous grain structure and calcia was only dissolved in large zirconia grains. This means that calcia promoted grain growth of zirconia particles.