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

Abstract

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 (CI), 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-T G analysis was carried out on all samples. Powders fired for 12 h at 500 and 900°C were sieved at 60 μm, uniaxially pressed at 20 MPa, and fired for 2 h at 1500 and 1600°C. 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-Z rO₂(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.