Synthesis and mechanical properties of lanthanum oxide (La2O3)doped 8 mol % yttria-stabilized cubic zirconia (8YSZ)

In this study, 8 mol % yttria stabilized cubic zirconia (8YSZ) powders as a matrix material and 0-15 wt% La
2
O
3
powders as an additive were used in order to determine the effect of La
2
O
3
addition and amount on the phase stability, microstructure and mechanical properties of 8YSZ. XRD results showed the existence of cubic and hexagonal crystal structures for all addition amounts. Besides, La
2
O
3
up to 5 wt% was completely dissolved in the crystal structure of 8YSZ but, La
2
O
3
with higher than 5 wt% reacted with 8YSZ at high temperatures and formed pyrochloric La
2
Zr
2
O
7
compound. The hardness values of 8YSZ decreased and fracture toughness increased with the increase in La
2
O
3
amount.