Influence of synthesis method and praseodymium doping on stability and sintering of Ca stabilised zirconia

The effects of doping with praseodymium and of preparation method on the Ca-FSZ (fully stabilised zirconia) system were studied. Samples were prepared by a ceramic method (CE) and several sol-gel methods, namely colloidal (CG), citrate (0), and polymeric (PG). Two samples with the compositions (ZrO2)(0.7)(CaO)(0.2)(Pr2O3)(0.05) (doped) and (ZrO2)(0.8)(CaO)(0.2) (undoped) were prepared by each method, in order to study the influence of praseodymium doping. DTA-TG analysis was carried out on all samples. Powders fired for 12 h at 500 and 900degreesC were sieved at 60 mum, uniaxially pressed at 20 MPa, and fired for 2 h at 1500 and 1600degreesC. The resulting compacts were characterised by XRD, SEM-EDX, Vickers microhardness testing, and density and lattice parameter measurements. The results indicate that the praseodymium enters the CaO-ZrO2(c) solid solution, improving densification and microhardness. Samples prepared by sol gel methods showed better densification and higher microhardness than samples prepared by the ceramic method. Citrate samples stood out for their non-porous microstructure and high Vickers microhardness.