Effect of Rare‐Earth Dopants on Mechanical Properties of Alumina

We report here about the effect of rare‐earth dopants on the improvement of room‐temperature mechanical properties of alumina. Rare‐earth ions (RE = Yb 3+ , Er 3+ , and La 3+ ) of different ionic radii in a minimum concentration of 1000 ppm were added as dopants individually to high‐purity alumina and densified by pressureless sintering. High strength of about 700 MPa was attained for Yb‐doped alumina sintered at 1400°C. And, high toughness of about 7.0 MPa·m 1/2 was attained for Er‐ and La‐doped alumina samples.