Effect of La2O3 addition and sintering mode on the mechanical properties and microstructural evolution on an 8YSZ ceramic alloy

Abstract In this research, the influence of La 2 O 3 addition on the microstructure, phase stability and mechanical properties of 8 mol% yttria stabilized zirconia (8YSZ) was studied. 8YSZ with La 2 O 3 (9, 12 and 15 wt%) ceramics were fabricated by microwave and conventional sintering at 1400 °C/ 20 min and 1400 °C/ 5 h, respectively. Irrespective of the sintering technique, the relative sintered density was found to decrease with increasing amount of La 2 O 3 . The grain growth of 8YSZ was enhanced significantly by the addition of La 2 O 3 . The XRD results demonstrated that addition of La 2 O 3 up to 15 wt% did not disrupt the cubic 8YSZ phase regardless of sintering technique; additionally evolution of pyrochlore phase, La 2 Zr 2 O 7 was observed in all sintered specimens. Vickers hardness of 8YSZ ceramic compacts were also found to decrease with increasing amount of La 2 O 3 .