Effect of Cation Doping on Mechanical Properties of Yttria Prepared by an Optimized Two‐Step Sintering Process

Undoped Y 2 O 3 and Y 2 O 3 doped with either Si 4+ , Er 3+ , Yb 3+ , Al 3+ or Ti 4+ were fabricated by a two‐step sintering method. The concentration of each dopant cation ( Si 4+ , Er 3+ , Yb 3+ , Al 3+ , and Ti 4+ ) was adjusted so that the dopant:yttria molar ratio was 0.01 and the mechanical properties and the microstructures of each were characterized. The Vickers hardness and the bending strength of cation‐doped Y 2 O 3 increased in the order Si 4+ , Er 3+ , Yb 3+ , Al 3+ , and Ti 4+ paralleling increases in the relative density. Ti ‐doped‐ Y 2 O 3 had the highest density and the highest strength. Transmission electron microscopy analysis revealed that Ti segregated to the grain boundaries of Y 2 O 3 . The two‐step sintering method was optimized to enhance the mechanical properties of Y 2 O 3 . As a consequence, Ti ‐doped Y 2 O 3 with the Ti 4+ :yttria molar ratio of 0.01 sintered at the optimized heating schedule was found to have a Vickers hardness and three‐point bending strength as high as 874 Hv and 307.0 MPa, respectively.