Synthesis and mechanical properties of lanthanum oxide (La 2 O 3 )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.