The effect of microstructure control on mechanical properties of 12Ce-TZP via two-step sintering method

The nanopowders of 12Ce-TZP were synthesized by a solid state reaction method and the effect of two-step sintering (TSS) on the microstructures and mechanical properties of the ceramics were studied. The samples obtained by conventional sintering (CS) exhibit approximately 2.5 μm in grain size and only 6.99 GPa in Vickers hardness, as well as 425 MPa in bending strength. To control the microstructure and consequently optimize the mechanical properties, different TSS regimes were conducted. The results indicate that first firing at 1450 °C for 1 min followed by cooling down to 1300 °C with a soaking time of 30 h results in a highly densified (98.4% TD) ceramic with optimal mechanical properties (9.22 ± 0.26 GPa, 14.7 ± 0.66 MPa m1/2, 501.40 ± 16.21 MPa) and without significant grain growth (∼1 μm). This provides an economic and effective approach to controlling the microstructure and thereby improving the mechanical properties of 12Ce-TZP ceramics.