Synthesis and mechanical characterization by nanoindentation of polycrystalline YAG with Eu and Nd additions

Mechanical properties measured by nanoindentation of ceramics of pure YAG, as well as doped with 2 and 5 at% Eu and Nd synthesized by a modification of the Pechini-type precursor method that includes the formation of spherical agglomerates by spray drying, are reported. The densification of sintered doped samples was successfully achieved at temperatures as low as 1550 °C in air using nanometric-sized powders produced by high-energy ball milling. A slight increase in the lattice parameter due to Eu and Nd additions to the YAG was observed, as expected, but effectively no change in mechanical properties was observed. Within the standard deviation, the hardness was 22 GPa and the elastic modulus was 315 GPa for all samples. These values are more than twice as large as those previously reported for amorphous fibers prepared with the same compositions but similar to literature reports for single crystals.